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GULLIVER v5.3 (2004.04.12) | Copyright 2004 T.Bone | T.Bone's GURPS Diner

Book 6: Damage and Dangers

Taking It and Dishing It Out in GURPS


This Book is full of improvements for GURPS combat mechanics that only work well at human scales. It reworks other dangers as well: falls, collisions, cold, and so on. Your character's size can make a big difference in whether she survives these hazards or not!

Another topic covered is that eternal online debate: are GURPS' Fatigue rules broken, and if so, how do you fix them? Following that is a discussion of realistic sustenance requirements and life spans for nonhuman designs, possibly a first for a game supplement! And plenty more.

Size and Damage

No special rules are needed to cover the basics. A Giant does lots of damage based on its ST, and an Ellyl does little. Dragon teeth are big and kitten teeth are small. Apply the appropriate damage to the target's HP and go from there.

ST and Damage

Combat ST vs Load ST

Under GULLIVER rules, damage from punches, hand weapons, bites and any other direct application of ST is figured from Combat ST, not Load ST. (Load ST can be used to hurt indirectly, such as by picking up and tossing a foe.)

All-Out Attack damage

GURPS allows characters to add +2 points of damage with an All-Out Attack. But a straight +2 means +2 whether it's a slap from a ST 6 weakling or a battleaxe smash by a ST 17 bruiser.

For a more realistic effect, add +33% damage, rounding up, instead of +2 points. This will please the high-ST players in your game, and provides appropriate results for characters of any size.

Handling Tiny Damage

Despite appearances, GURPS isn't actually saying that an attacker of ST 4 or less does no damage. It's saying that the attack does damage so puny it's of no concern to the standard human. Of course, to a Cidi a "mere" ST 4 blow is pretty hefty, and should be gamed as such.

An ideal system would "scale" damage neatly with ST. The simplest reworking would have ST 20 deal twice the damage of ST 10, ST 30 three times the damage of ST 10, and so on. Bringing weapons into the fray, a ST 40 Giant with an appropriately giant shortsword would do 4 times the damage of a ST 10 human with a normal shortsword. For low ST scores, damage gets appropriately small: ST 2 dishes out one-fifth the damage of ST 10, which can be rounded as appropriate (i.e., ignored if too small), or applied as fractional HP loss to small creatures for whom those fractions matter.

That's all intuitive and neat. Unfortunately, the GURPS damage progression doesn't scale so neatly (see the Appendix for one that does), but it's often close enough at the high end to be of use if you're not too picky.

At the low end, Vehicles 2E p. 97 offers a suggestion for fractional dice of damage:

The above makes for a rough solution, but it works well enough. The GM will have to make judgment calls on creatures with really low ST, until a neater ST damage progression and an "any-size-goes" melee weapon design system come along. Or head for the Scaling the Game rules in Book 8, which cover turning the tiny stats of puny combatants into more typical, easy-to-use stats.

Handling Split HP

That's split HP, not HT. Split HT means you have HT 12/28, which is HT 12 and HP 28. No big deal; HT and HP are separate things anyway.

But creatures like Centaurs can require two separate HP scores, one representing a "big half" and the other the "small half". Here are some ideas for playing this:

Pick one of the two body "halves" as the HP "base". Its HP are your character's base HP. Damage to that body "half" has normal effect.

Damage to the non-base "half" is applied to the same HP pool, but with a multiplier equal to (base HP / non-base HP).

Example: Your Centaur has HP 24 on bottom, HP 12 on top. Say you pick the horse half as the base, to give him 24 HP overall; damage to the horse half works normally. Damage to the human half, though, is multiplied by (24 / 12 = 2) before being applied to HP 24.

Alternately, pick the human half as the base, call your design HP 12, treat damage to the human half normally, and multiply damage to the horse half by (12 / 24 = 1/2).

Using GULLIVER rules for the treatment of HP, it won't matter at all which you choose; the effects will be the same. In general, it's easier to go with the larger HP, as you'll multiply rather than divide when the other half is hit. (And obviously, it's all easier to game when the larger HP is a neat integer multiple of the smaller. Design your creature that way.)

You're on your own in winging other effects: for example, will a tranquilizer dart take effect more quickly if you target a Centaur's human half, or is the creature an undifferentiated, horse-size mass for purposes of resisting? You be the judge.

See Book 3 for notes on hybrid creatures and buying split HP.

All About Blowthrough

"Blowthrough" is the maximum damage you take from a bullet or impaling wound. After inflicting some number of basic hits, the weapon passes through the body, doing no more damage. (See BS p. 109.)

How much damage?

A correction to the rulebook: blowthrough damage for any target should be set at some multiple of HP, not HT. For a standard torso hit, damage greater than straight HP blows through the torso and is lost.

A flaw remains: the rules increase blowthrough for characters who bought Extra HP as innate toughness, letting a weapon inflict more damage before passing through. To fix this, ignore Extra/Reduced HP when computing blowthrough. HP adjustments for size, on the other hand, definitely matter!

Example: Grog the Big has base HT 12 , HP 15 (he's a mutant with redundant organs, tough to put down), boosted to HP 30 for his Size +2. When the bullets start flying, base blowthrough damage on HP 24 (HP 12 times Linear Scale), not HP 30.

But this still penalizes high-HT characters – a HT 14 human suffers 14 points of damage before blowthrough, while Joe Average takes only 10.

Improved rule: An even better solution:

Set blowthrough damage at 10 points, scaled for size (i.e., 10 points x Linear Scale).

Example: Grog takes 20 points of damage before blowthrough, and no additional points for his high HT and base HP.

Using this rule, weakly PCs with low HP for their size will take a relatively high level of damage from blowthrough, which of course makes sense. Tough PCs with lots of HT and HP for their size will better survive piercings. This is probably the fairest solution for all characters, and is simple too.

Blowthrough modifiers

The deadliness of having having a hole rammed through you depends largely on where that hole was made! There's a x3 blowthrough multiplier for the vitals or head (but not the brain; rather, there's no maximum damage for injuries there, and blowthrough isn't used). A bullet or rapier in the chest will inflict up to 10 x 3 = 30 points of damage to the average person, before passing through.

Muliply blowthrough by x1/2 for limbs, x1/3 for hands or feet.

Beam, fireball, and lightning attacks double blowthrough for the torso, head, or vitals.

Creatures with odd shapes or compositions may further modify blowthrough levels; see blowthrough notes in Book 3.

Bullet size and damage

Then there's the matter of the size of that hole: is it a narrow, nearly bloodless channel, or a gaping cavern that lets the wind through?

Be sure to modify blowthrough for bullet type and size: x1.5 damage for slugs of .40 caliber or larger, x1.5 damage for hollow-point bullets, etc. Bullet damage in GURPS tends to be high, and thus is often limited by blowthrough, not damage dice; the multipliers are important in ensuring that a massive .44 round punches a more lethal hole than a .22 round, just as it should. 

Damage and Shock Meta-system

Damage and Shock in GURPS

Problems with HP levels

GURPS' rules for damage and injury are centered on human scale, which causes trouble at more extreme ends. It's odd to have both a HT 10/1000 Elder Octopoid and a HT 10/1 rat make the same death rolls at -10 HP and every -5 HP thereafter. And how do you work the "slowdown from injury at 3 HP" rule with the rat when it starts with less than 3 HP?

CII p. 152 offers help, distinguishing HT from HP. But the rules introduce another table, get tricky with regard to when to use HT and when to use HP for determining damage "levels", and still don't scale too well: a hulking HT 10/10,000 bioship rolls for death at -30 HP, the same as a HT 10/30 Giant.

Problems with HT rolls

Similarly, GURPS suggests certain HT rolls that don't work well for characters other than the generic ST 10 human (and sometimes not even then). Consider the "crushing attack to the vitals" rule, which forces a HT roll to avoid knockout regardless of damage:

Player 1: "My Pixie kicks your Ogre in the chest."
Player 2: "Ha! I don't even feel it! It tickles!"
GM: "Roll your HT, Ogre. Whoops, tough luck – you're out like a light."

The results are silly even if you substitute a human for the Ogre.

Too many rules

Hits on specific body targets in GURPS can require special HT rolls to avoid knockout, or stun, or sometimes both. High Pain Threshold helps resist some of those, but the bonus changes when resisting Pain spell effects. Stunners and nerve guns carry their own unique HT rolls (but with no DX/IQ penalty at all from a stunner should it fail to stun). There are special rules for dropping weapons due to pain from the Spasm spell and whips, but not from the Pain spell or a plain old whack on the hand with a stick. Eye gouges and face-pull attacks offer their own mechanics. All with no rules in sight to explain how a Pain spell might work on mice and Giants.

Improving things

Shock in GURPS is more messy and complex than it should be. It's simpler to replace all the special rolls and rules with a comprehensive, works-everywhere system:

  1. Instead of special rules for stunning and shock effects, treat shock like damage: measure it in points in all situations, and apply the effects of those points appropriately.
  2. Toss out the HP tables, and make the effect of points of damage and shock proportional to HP.
  3. Use HP to determine the amount of damage or shock that causes any given effect, and HT as the roll to resist those effects when such a roll is called for.

Those simple guidelines can cover pretty much everything. Stun wand vs hippopotamus? No problem!

Effects of Damage

Computation of damage points needs no explanation here. Modifiers for attack type and hit location are per GURPS (use CII p. 53).

The following effects are the result of actual damage, not shock. What matters for effect purposes is damage points relative to HP. Damage levels are extrapolations from the effects of damage on standard "HP=HT" humans. The suggestions are intuitive, scale perfectly, and bring the same proportionate effects to humans, mice, elephants, and bioships.

Generally, Strong/Weak Will does not affect HT rolls to resist effects.

Slowdown from injuries

Halve Move and Dodge when HP are reduced to less than x1/3.

This mirrors GURPS' slowdown rule.


You fall down on damage of over HP x1/2 and a failed HT roll.

This mirrors GURPS' knockdown rule, and is separate from falling down after knockback from a collision.

Crippled limbs

An arm or leg is crippled on damage in one blow of over HP x1/2, a hand or foot on damage over HP x1/3. Excess damage is lost.

Instead of the automatic stunning rule, compute shock points normally for the wound, but double for the added trauma of crippling.

Except for the change to shock, this is the same as the GURPS rule.


Yuck. A single cutting blow inflicting twice the damage needed to cripple a limb (i.e., over HP damage for an arm or leg, over HP x2/3 damage for a hand or foot) amputates it on a failed HT roll. Amputation is automatic if damage is twice that amount.

Actual damage taken, though, is equal to the amount needed to cripple the limb; excess damage is lost.

Double shock for the trauma of crippling/amputation.

This is a new rule.


Crippling damage for a neck is the same as a leg or arm.

A crippling blow "cripples" the neck and paralyzes the body (attempt recovery roll normally). An amputating blow decapitates, or fatally breaks the neck if crushing.

This is a revision of the GURPS decapitation rule.


Roll vs HT each turn while at HP 0 or less to avoid unconsciousness.


Roll vs HT at -HP and every -HP x1/2 thereafter. Automatic death is at -HP x5.

Recovering from Damage

It makes sense to let wounds heal in proportion to size: a night of rest and a HT roll heal HP/10 damage (which will be 1 point for most PCs). See Effects of Shock for hints on rounding this number.

As an option, allow success by 10 or more points on this HT roll to heal twice that much damage (2 points for most PCs), success by 20 points heal three times as much, etc. This allows some pretty speedy healing for high-HT characters, especially those with the Rapid Healing advantage.

The Regeneration ability should use the same HP/10 base for increments of healing.

Regrowth: Realistically, growing back lost body parts is a quicker task for tiny creatures. Divide the speed of Regrowth by the square root of your Linear Scale to get this effect.

Measuring Shock

Let shock be measured in points in all situations, not just from weapon blows. Base shock points equal damage points, after modifiers. A cutting blow inflicting a final 6 points of damage inflicts 6 points of base shock.

Shock can further differ with weapon type, hit location, and other factors. Below are additional modifiers to base shock:

Body target:

Weapon type:

Target condition:

Other attacks

Handle shock from stun weapons with these same rules. Decide how many points or dice of shock the weapon inflicts, and apply normally. A weak stunner might inflict 2d shock, a strong stunner 4d. Some stun weapons inflict actual damage, such as 1d damage from a Type II Nerve Pistol; you can compute shock using a damage multiplier, such as x4.

Handle magical stun/shock spells in the same way: 1d shock from a Pain spell, for example. You might even let a mage "grow" a Pain spell to 3d size, like a fireball.

Effects of Shock

The following effects are the result of shock, not actual damage. What matters for effect purposes is shock points relative to HP.

Let Strong/Weak Will add to HT rolls to resist effects.

IQ and DX penalties

Apply -1 per (HP/10) points of shock, for one turn. This mirrors GURPS' regular shock rule.

Rounding: A suggestion for rounding: use the normal -1 penalty per point of shock for creatures with HP 8 to 14. Use -1 per 2 points of shock at HP 15 to 24 (which confers a nice combat benefit to a high-HP character), -1 per 3 points at HP 25 to 34, etc.

For low-HP creatures, use -2 IQ/DX per point of shock at HP 4 to 7, -3 per point at HP 3, -5 per point at HP 2, and -10 (!) per point at HP 1. Those numbers make sense: a HP 1 rat hit for a point of shock has taken the same massive shock as a human eating 10 points.

Stunning, general

You are stunned automatically on shock of over HP x1/2.

This mirrors GURPS' stunning rule

For a more interesting rule, let stunning occur on a failed HT roll on shock of over HP x1/3, or automatically on shock of over HP x2/3.

Stunning, blow to brain

Apply a x2 shock multiplier to brain hits, and use the general stunning rule above.

This replaces the GURPS rule.

Stunning, limb

An arm or leg is stunned on shock of over HP x1/2, a hand or foot on over HP x1/3. The character is not necessarily stunned, but items held by the stunned limb are dropped. (Allow an HT roll to maintain grip if shock is just enough to stun.)

Excess shock points are not lost, and can cause overall stunning.

This is a new rule, and replaces GURPS' special rule for whips and dropped items.

Knockout, general

Roll vs HT to avoid knockout on shock of over HP. Knockout is automatic on shock of over HP x2.

This is a new rule.

Knockout, blow to brain

Apply a x2 shock multiplier to brain hits and use the general knockout rule above.


Extreme pain applied continually may have psychological effects. Details are up to you, but it would take an incredible Will to resist constant pain of over HP points while remaining conscious (the intended effect of torture devices!), without breaking down in some manner. The Fright Check rules might be useful in determining effects.

Recovering from Shock


Use normal GURPS rules for recovery.


Unless specified otherwise, recovery from stunning follows the normal GURPS rule: roll vs HT each turn to recover. The same applies to a "stunned" limb.

IQ/DX penalty

The GURPS rule is that shock lasts throughout that turn only; it's gone on your next turn. (The shock effects of certain weapons, such as high-tech stunners, may last longer.)

That's all easy to play, and works fine in the game. It's possible to get a much more detailed effect, though:

Advanced rule: Roll vs HT to recover from the IQ/DX penalty. You reduce the penalty only by the amount by which the roll succeeds. For example, if you're at -3 IQ/DX from shock, roll HT on your next turn. Success by 1 or 2 removes that many points of penalty. Success by 3 or more removes it completely.

Failure on the HT roll means the penalty persists throughout the turn – during which you might pick up even more penalty points from further shock! Roll again next turn...

The rule is easy to play and has a great realistic feel – but it does add die rolls and makes combat deadlier for all involved. Try some sample fights before springing the change on everyone.

Wrapping Up

Examples applying the damage and shock rules:

Examples: A HP 1 rat would make death rolls at -1 HP, and every additional point of damage thereafter would force two death rolls. Automatic death occurs at HP -5.

A HP 120 dragon would suffer a -1 DX and IQ "shock" penalty for every 12 points of damage taken. At 30 HP, he'd slow down from injuries, and after passing out at 0 HP, he'd be in danger of death if HP dropped to -120. Further death rolls are required every additional -60 HP, with automatic death at HP -600.

Play with specifics as you like. For example, you might decide that a whip does extra shock only for purposes of DX/IQ penalties and stunning, and not knockout. (That'd be a good feature of any torture instrument.) You can always opt to ignore any single effect (knockout, stun, etc.) for a given circumstance, especially when exotic weapons and magical effects are involved.

And if that HP 120 dragon looks too impossible to kill, see the Appendix for a solution.

Exposure Hazards

Body size plays a role in the effects of hazards like freezing cold or a sea of flame. Consider a 2" mouse exposed to flame: with his Area Scale he has only x1/1000 the exposure of you to the flame. Sounds like he's far better off than you'd be – until you consider that that flame is acting on perhaps x1/30,000 the body mass! It's that "cube-square law" in action: he should be char broiled but quick.

Hazards for use with these rules include acid, flame, heat, cold, sunburn, poisonous gas or atmospheres, and electricity. On the other hand, hazards like altitude, snow blindness, and rapid decompression won't be particularly affected by size or shape.

Simple Rules

The simple way to get this effect is to make up appropriate damage for odd-sized creatures exposed to hazards like heat or cold. Small PCs have to take less absolute damage than normal-sized ones, but more damage relative to their small HP. A large creature should take more absolute damage than a human, but less relative to its large HP. Wing the numbers to this effect.

Detailed Rules

Base damage for hazards is usually expressed as damage taken by a human. You'll want to modify this base as per the simple rules. Below are guidelines.

Two damage modifiers are at work:

The advanced rules look at these separately, but if you have (roughly) human proportions, the net result is this:

Multiply base damage by the square root of your Linear Scale.

If you're a Giant with Linear Scale x4, take double normal damage from environmental hazards. (Not to worry, you should have four times human HP.) If you're a two-incher with Linear Scale x1/36, take one-sixth normal damage. (Too bad you only have one-thirty-sixth human HP.)

This gives you the effects described under Simple rules, and is reasonable for a creature of any size, without unusual surface area or density.

Advanced Rules

No change from the above, other than to unveil the geekery behind it:

First, adjust damage for the smaller area you present to the attack: a small creature gets a smaller "dose" of exposure than you do. Area Scale is the key, but to mesh this with the way HP are scaled, use the square root of Area Scale. Unless you have an odd surface area, that'll be the same as Linear Scale.

HP scale with Linear Scale too, so that leaves big and small creatures taking the same proportionate HP damage. Now consider that "cube-square" problem:

Take your ratio of area to mass, using the inverse of your MAR (i.e., 1/MAR). The result will be greater than 1 for Leprechauns, less than 1 for Giants.

Take the square root of the result, and multiply damage by that.

The net result for non-exotic creatures will be that in the detailed rules: absolute damage multiplied by the square root of your Linear Scale. But by doing the full calculations you can get exact results for creatures with exotic densities or unusual surface areas.

Miscellaneous Notes

Jet attacks

The rules for jet attacks in Book 5 are these exposure hazard rules, with the fixed-size nature of the attack handled appropriately. The jet carries a fixed level of damage; damage reduction for small size depends on target size relative to jet width, not target size relative to human size.

It's up to you, though, whether cube-square considerations should affect damage from a cone of fire, or whether that's not worth worrying about. If you go for the detail, use the calculations from the Advanced rules above to properly combine cube-square effects with the Book 5 jet rules:

Example: A foot-wide jet of flame does 1d damage. A 3" PC takes an initial x1/4 damage for reduced exposure; if he has a area-to-mass ratio 20 times a human's, multiply his damage by x4 (= roughly the square root of 20). Net effect: he takes a full die of damage, even though most of the jet washed over him – and that's a lot of damage for his HP. Small things cook up crispy!

A Giant, meanwhile, takes a human-sized 1d to start with – that's as big as the jet gets, even though the Giant's bigger. But that damage will be cut if you add cube-square effects; the Giant has lots of protective mass relative to the surface area burned.

Non-damage effects

Rules for exposure don't always measure effects in damage. Handle appropriately: for example, you can modify the effective rads taken from radiation in the same manner as damage.

Other exposure might involve fatigue or HT rolls, not damage. Non-extreme heat or cold are examples. How can you apply exposure effects?

If the exposure causes fatigue, modify fatigue in the same manner as damage.

If HT rolls are involved, use a penalty equal to half your Size: -4 for a Size -8 creature, +3 for a Size +6 character etc. (Intense GMs can use more exact surface-to-mass ratios for odd creatures: if you're Size -4 but with a high density that leaves you with the same area-to-mass ratio as a Size -2 humanoid, your HT penalty is only half of that -2, or -1.)

Remember that cube-square effects cut both ways: a tiny PC baking in the sun can also cool down quickly in the shade. A warm room will heat him quickly on a cold day.

More on freezing

When resisting freezing, insulation helps. Add +1 to HT rolls for Overweight, +2 for Fat, and +3 for Obese.

Cold has another special effect: numbness, especially in the extremities. GMs may wish to lower DX by 1 for every one-third Fatigue or HP lost to cold. (Realistically, smaller body parts suffer even more. Manual dexterity is particularly quick to go in cold weather; apply additional penalties as you see fit.)

Note that the GURPS rules for succumbing to heat and cold require rolls every half-hour to resist loss of one Fatigue or HP. As temperatures get more extreme, the chance of missing this HT roll increases, but the degree of effect itself doesn't change at all – a wet, naked PC in a raging Antarctic blizzard will still lose only 1 Fatigue per half hour. That's too slow.

A fix for this: lose 1 Fatigue or HP for every full or partial 3 points by which the HT roll was missed. The more extreme the temperature, the quicker you go. Space the loss of points: a loss of 6 Fatigue for the half hour means 1 fatigue every 5 minutes.

Advanced rule for water: Water conducts heat away from a body far more quickly than air does. Swimmers will feel cold in water of a temperature that would be comfortable as air temperature; they'll suffer hypothermia in a surrounding temperature that would be quite survivable on land.

Simulating this is pretty easy. First, set a single, optimal environmental temperature within the creature's temperature "comfort zone". For a human, this might be 70°.

Now take the difference between water temperature and that central temperature of the immersed creature, and triple that for purposes of effect. For example, if your optimal temperature is 70° and you're in 60° water, treat that as a 10° x 3 = 30° difference – it's as if you're spending time in 40° air, which is getting cold for a human.

This rule applies equally to aquatic creatures; it's just a tough part of the environment they live in, and explains why many fish are so sensitive to temperature differences – in water, a small difference is a big difference. (The rule does not affect the "stiffen up" temperature of a Cold-Blooded creature; that's based on absolute temperature.)

See Book 3 for more on setting a character's temperature tolerances.


Realistic handling of collisions should start with all that physics class stuff about masses and velocities, and boil those down into easy rules that still get the basics right. PCs aren't billiard balls on frictionless surfaces, though, so it's OK to take liberties Newton would not have approved of. The rules below do so, and, for better or worse, attempt to express steps in English instead of mathematics.

Existing GURPS rules for collisions include the Basic Set falling rules and Vehicles' collision rules. With average damage rolls, the typical HP 10 human takes a deadly 45 points of damage from a 50 mph (30 yard) fall using Basic Set rules, but walks away with only 8 or 9 points of damage in a 50 mph Vehicles collision. GULLIVER rules will hand out a middling 30 or so points in either situation (though the exact amount will vary with the details of the collision).

Damage numbers won't necessarily behave properly when applied to vehicular collisions using Vehicles stats. Vehicles scales HP in a way very different from GULLIVER and GURPS scaling for creature HP; this is an unresolved "bug" in GURPS. See Book 8 for ideas on integrating Vehicles with GULLIVER.

For simplicity, these rules assume nice inelastic collisions: things don't "bounce" interestingly. That makes post-collision speeds fairly easy to compute. For more elastic collisions, hit the physics books.

Speed of Impact

Start with combined speed of impact: add velocities for a head-on collision, subtract the slower from the faster for a rear-end collision.

Example: Green is coming from the left at 40 mph, Yellow from the east at 50 mph. Their combined speed is 90 mph.

If Yellow hit Green from the rear instead, the speed of collision would be only 10 mph.

For collisions at angles, guess at things or get a physics book. In a right-angle collision, damage comes only from the object which does the striking – i.e., the one that broadsides the other. (If they strike each other equally, average their two velocities as the combined speed.)

Speed Change

What happens next? Velocities change. Take the mass of either object: what's its percentage of the combined mass of both objects? That's the percentage of combined speed that the other object takes as speed change.

This is usually easy to eyeball. If the objects are of equal mass, each takes half of combined speed as speed change. If Blue is nine times as massive as Red, then Blue is 90% of the combined mass and Red is 10%. Blue's speed change is 10% of combined speed, Red's is 90% of combined speed.

Each object's speed change happens in the direction the other object was moving.

Example: Green (1000 lbs.) is coming from the left at 40 mph, Yellow (500 lbs.) from the east at 50 mph (combined 90 mph). Green's proportion of total mass is two-thirds; Yellow's is one-third.

Green's speed change is one-third combined speed, or 30 mph; Yellow's is two-thirds combined speed, or 60 mph.

Green's speed changes 30 mph back to the left, so becomes 40 - 30 = 10 mph. Yellow's speed changes 60 mph back to the right, so becomes 50 - 60 = -10 mph (i.e., 10 mph in its backward direction).

Example: A 10-ton semi-truck coming at 60 mph collides with your PC. No need to mess with math: from respective masses, the truck's speed change will be almost 0, while your speed change will be almost the full 60 mph. That's your new speed, in the direction of the truck (and firmly embedded in the grill).

Note that the results would be the same if you flew at 60 mph into the stationary truck: you'd suffer essentially 60 mph of speed change, in the direction of the truck's travel. (It's stationary, so you stop dead.)

Loss: A little energy is lost in the process. Don't worry about it, except to quickly round numbers or overrule odd effects. The above stationary truck might receive 1 mph of speed change from the above calculations, but friction with the ground will absorb that much change. Too bad, if you were sacrificing Captain Speedo's life in the hopes of nudging that evil truck over a cliff.

Dice-based speed change

Book 5 uses these collision rules for combat slams, with one addition: an optional ST-based Contest for determination of speed change. It's the same system, with a random factor added.

You can use either the "mechanistic" collision rules here, or Book 5's Contest, to determine speed change in any collision – animate or inanimate, powered or unpowered. In general, though, the Book 5 Contest "feels right" when one or both sides in the collision is an animated slammer. The mechanistic rules for speed change feel right when both sides are inanimate objects.

Collision Damage

Next, compute damage. Each side computes a damage score based on its own speed change and mass – but the higher of these damages applies to both objects.

After that, modify the damage each side suffers for the hardness of the other side. Finally, reduce damage suffered by each side for its own ability to absorb damage.

That's a few steps, but it plays quickly for typical objects like people, while remaining flexible enough to handle a wide variety of situations.


Compute damage for each side as 1d per 10 mph of its own speed change. Don't apply damage yet, though.


With apologies to calculator haters, multiply speed-based damage dice for each side as follows:

multiply damage by the square root of (own mass in lbs. / 150)

That's roughly the square root of Volume Scale for many characters, and is 1 for the average human. Once you've computed it for a character, jot it down on his form for easy recycling. You might want to recalculate if the character gains or loses a large amount of carried items, but don't bother recalculating because he picks up a battleaxe.

Note that for each side, you're multiplying damage for its own mass. Small things start and stop on a dime; big things suffer horribly doing the same. This may differ from collision rules found in every other RPG, but that makes it the only right rules set out there. Imagine the scene: a toy Tonka truck has far fewer HP than a real truck, but throw both into a cliffside at 50 mph, and it's the Peterbilt that comes off far worse.

Applying damage

Take the damage dice scores calculated so far for each side, and apply the higher to both sides. In general, this will be the damage computed for the smaller object.

Example: When a motorbike weighing 600 lbs. (with rider) crunches into a tank at 40 mph and stops dead, the bike suffers 40 mph of speed change and all attendant damage. The much heavier tank's computed speed change will be nearly zero – as will its computed damage, despite the high multiplier for the tank's mass.

Both vehicles suffer the higher of the two damages, which is the impact of a slamming motorbike. That's (40 mph speed change x the square root of (600/150) = 8d).

After that, there are a couple more factors to account for:


Multiply the damage dice suffered by each object for the hardness of the other object:


damage multiplier

Very hard (stone, concrete, metal, etc.)


Hard (packed soil)


Yielding (soft soil, other character)


Soft (mud, sand)


Liquid (water) see Falling below

x1/2 or less

Very soft (air bag, mattress)


A sharp point is generally very hard, and further inflicts impaling damage!

Example: In the above example, both objects are hard steel. Each side multiplies damage dice received by 2.


You've now got the damage dice each side takes; go ahead and roll separately for each.

Damage absorption

Characters have an ability to absorb a certain amount of speed change: low-speed impacts simply don't hurt at all. That's largely because the impact from a collision with a large object is spread all over your person. You can simulate this by reducing rolled damage by some number based on your surface area – or the square root of your surface area, keeping in line with the way HP are scaled.

In fact, HP itself works great here. The rule:

Subtract a portion of HP from collision damage suffered so far:
half HP for widely spread (full-body) impact
one-fourth HP for localized impact
no subtraction for very localized impact.

There's your final damage.

Examples of a widely spread impact would be a collision with the big, flat end of a bus. Localized impact include slams, or a car hitting a person. A very localized attack is a collision striking a small area, such as the area hit in a weapon strike.

Don't forget that DR also protects against collisions. Some armors might protect fully against localized impacts but less against full-body impacts, as suggested by GURPS' falling rules.

Example: Rolling 16d damage, the above motorbike is in trouble. But subtract its DR and half its HP (for widely spread impact) from damage suffered in the collision.

The tank, struck against a much smaller portion of its size, should receive a lesser HP subtraction, for localized or very localized impact. But its high DR makes the problem moot.

Falling down

Getting knocked about by a collision may make you fall down. Make a balance roll, or see the knockback rules in Book 5 for detail.


What if something collides with you while you're against a solid wall? You don't go anywhere. Take damage based on speed and mass of the colliding object, not your own speed and mass, adjusting as appropriate for hardness.


The bang of collision can just be a start; it's a whole new world of damage when a large vehicle overruns a small one. As suggested by Vehicles p. 159, this may happen when the colliding vehicle is 3 Size levels larger than the other.

If you like, use Book 5's trampling rules for all overrun situations. This sets trampling damage dice as the square root of (weight in lbs.) / 20. However, the resulting numbers don't seem to do justice to the effects of a milk truck backing over a scooter; vehicles' rigid structures seem especially vulnerable to crushing weights. Double trampling damage when one vehicle is overrun by another.

The conditions for overrun: you must collide with your target and be the same Size or larger if your vehicle has legs, or 3 Size levels larger if you have wheels or other ground propulsion. (What's important is tires roughly taller than your target; appropriately-sized Monster Truck tires help!)

Handle special situations appropriately. A skilled dirt bike rider can "overrun" a parked car. A bike knocked flat in a collision is a Size level smaller for overrun purposes. And so on.

Powered Collisions

This section borders on advanced rules, so ignore if you like – but it does look at an interesting detail. What if an object powers its way into a target – engine roaring, jets thrusting, legs straining forward? It's pushing throughout the moment of collision, instead of just coasting passively in!

Turn motive power into a higher effective mass for collision purposes. If the object has a Load ST score, let effective mass be mass + (Load ST x 10 lbs.).

If the object has a vehicular thrust rating or kW engine power rating, the job is tougher – there are no clear guidelines at all for equating these with creature ST. Try this: Add a vehicle's engine kW rating x 10 to effective mass if it's accelerating forward. If it has a thrust rating instead, add thrust to effective mass if in water, thrust x 0.1 if in air.

These are completely arbitrary numbers that may be a magnitude off from more proper conversions, but in the meantime they do something.

Advanced rules

Torque: Multiply the bonus to effective mass by 2 if the vehicle is traveling at less than 1/4 top speed, and multiply by 1/2 if the vehicle is traveling at over 1/2 top speed. This represents the greater acceleration of power systems at low speeds.

Traction: The extra effective mass from power only works if you can effectively push forward. For ground objects, the extra mass bonus from power will be the lower of what you've computed so far, and:

The use of object weight instead of mass is intentional.

Vehicles and traction: Take the Off-Road Speed multiplier calculated from a vehicle's Contact Area and Ground Pressure, from Vehicles p. 130. Multiply the extra mass bonus from power in a collision by that same multiplier. The effect is that a low ground pressure – i.e., a lot of contact with the ground – provides the traction that lets your engine add oomph to a broadside. A high ground pressure represents little traction to keep you plowing forward.

Power and damage

In powered collisions, use effective masses not only to compute speed changes but to compute mass-based damage multipliers as well. Objects that accelerate into each other will hurt each other more than those that coast to a crash.

Example: If the above 600-lb. motorbike has its 30 kW engine at full throttle when slamming that tank, it'll hit harder than it would by coasting into the collision.

Let's throw in the advanced traction rules, too. Assume standard traction. Compute the bike's effective mass bonus as the lower of (30 kW x 10) = 300, and (600 lbs. x 1/2) = 300 – it's 300 either way. The bike slams with an effective mass of 600 + 300 = 900 lbs. That won't make any real difference in terms of pushing the giant tank, but will increase damage for all involved.

Wrapping Up

The collision system meshes with other aspects of GURPS. Vehicles also scales damage linearly with speed (if not necessarily arriving at the same final numbers as these rules). Even damage from thrown weapons somewhat scales with speed in GURPS: speed presumably scales with ST, and damage more or less scales with ST.

The damage muliplier for mass agrees roughly with Vehicles' collision damage modifiers for weight, which scale with vehicle weight to the two-thirds power, based on vehicular HP. The difference between that and GULLIVER's square root-based scaling isn't large.

GULLIVER turns to the collision rules a couple more times for falling and combat purposes, but stops short of suggesting a unified meta-system handling all things kinetic, from a mace upside the head to a dive into a dry pool. Yes, it could be done, but it's a task for the energetic.

Extra credit question

The rules scale damage with speed – but you're thinking damage should scale in some way with kinetic energy, or the square of speed times mass, right?

By computing damage from speed times the square root of mass, you essentially are using the kinetic energy equation. You're just taking the square root of it all, which is fine. It's an artificial adjustment that lets things play nicely with the scaling used for the artificial units known as Hit Points.


You can drop a mouse down a thousand-yard mine shaft and, on arriving at the bottom, it gets a slight shock and walks away. A rat is killed, a man is broken, a horse splashes.

— J.B.S. Haldane, "On being the right size", 1928

What's a fall but a collision with the Earth? For simple rules, you've got what's on BS p. 131. But for detailed rules, especially when odd-sized non-humans are involved, you'll really want to bring mass into the equation. The collision rules above provide all the basics you need. Geronimo!

Speed of Impact

Speed, distance fallen and time are all spelled out in a lovely table here:

Falling Table (for 1-g)

speed in y/sec  

speed in mph

yards fallen

time in seconds

base damage* 








































































































































































All results are rounded, but remain pretty close to exact calculations.

Note the asterisk by base damage. The same damage modifications used in the Collision rules come into play here.

The table introduces damage die adds and divisions at low velocities to keep things smooth. Remember, 1d/10 is meaningful damage for a tiny critter with a fraction of a Hit Point.


For any given falling time, multiply speed by local gravity.


Let Catfall or a successful Acrobatics roll subtract 20 mph from effective impact speed. For those without such abilities, even a DX, Judo, Wrestling, or Breakfall maneuver roll should allow a 10 mph subtraction.

GURPS has no specific Breakfall skill – the general stuntman skill, not the judo Maneuver. Such a skill might be P/E, with a successful roll subtracting 20 mph plus 2 mph per point of success from impact speed.

Leg power

An optional bit of detail: If you can land neatly on your feet, you can use leg power to break the fall. This subtracts speed from your impact equal to the speed at which you can jump upward – 3 yards per second or so for a typical human. (You can figure exact jumping speed for any creature from Book 4.) For a power-leaping Super, this can mean quite a reduction in hurt!

Of course, you're not likely to land so neatly after an ungainly or long fall; the GM may rule the feat impossible, or require a roll against DX, Jumping, Acrobatics, Breakfall skill (above), or Bouncing superpower skill to make a perfect two-point landing.

Terminal velocity

Terminal velocity is the speed at which acceleration from gravity is offset by deceleration from drag. That sets a limit on your speed during a long fall, and on the deadliness of impact.

Calculation of terminal velocity, or tv, is detailed in Book 4. A quick fudge is 100 mph times the square root of your Linear Scale (x1 for a human), times the square root of local gravity (1.0 on Earth), divided by the square root of local air density (with 1.0 being "normal" air density near sea level).

That's tv in a spread-eagle "flat" pose for maximum drag. Humans will reach that speed after about 5 seconds of falling (for game purposes), if the Earth doesn't intervene. You'll fall faster if you reduce your surface area through a diving pose – set this "diving tv", or dtv, to an arbitrary tv x1.5 for game purposes.

Falling limp or unconscious, you might hit a speed somewhere between the above two: multiply tv by x1.25.


If you trip and fall, treat that as a fall from a height equal to your linear dimension, or half that height on a balance or Breakfall roll (with Half modifier for encumbrance). Multiply distance by x2/3 for semi-upright posture or low stance, and x1/2 for horizontal posture or very low stance. These are cumulative.

A critical failure on the roll might mean a localized impact on a randomly rolled body location. Such an unlucky fall can break a limb or fracture a skull.

For most creatures, especially small ones, damage won't even be worth rolling. But for huge beasts, a trip can be one-way.

Impact Damage

Damage is 1d per 10 mph of impact.


Multiply the damage you take for your own mass, as per the collision rules. That is,

multiply damage by the square root of (your mass in lbs. / 150)

Small, light creatures will bounce and scurry on; elephants will fall and not get up. This is realistic, even without the added effects of terminal velocity.

Surface hardness

Use the same hardness modifiers presented earlier: x2 for concrete or rock, x1.5 for hard soil, x1 for soft soil (or another character), x2/3 for mud or sand, and x1/3 for a stuntman's cushion.

Use a multiplier of x1/2 for a belly flop into water. Let proper diving form from a successful Swimming roll turn this into x1/5. Better yet, make this a roll against Diving skill. Call it P/E, defaulting to Acrobatics -2, Swimming -2, or Breakfall -2, and taking Half modifier for encumbrance. (Note, though, that proper diving form also leads to maximum terminal velocity!)

Damage absorption

Figure your damage dice using all the above modifications, and roll 'em. Now subtract half your HP from damage, per collision rules. Subtract only one-quarter HP if damage is not spread out nicely over the body: a clear landing on the head, a fall onto spiky rocks, etc.

A fall onto a single, smallish point – say, the top of a pole – is akin to being hit by a weapon: no damage subtraction at all. (And damage is impaling if the pole is sharp!)

Hit location: Normally you can consider falling damage as "whole body" damage and ignore hit locations. But if common sense, GM ruling, or some die roll indicates a fall onto one specific body location, that's a localized impact; allow only one-quarter HP subtraction, or none at all. Body location damage multipliers apply as well.


Let's take some examples of falling, using animals with scaled stats based on HP 10 and humanlike surface areas, and a thousand-yard mine shaft. They're unconscious and limp, so tv is multiplied by x1.25. Also assume a rock-hard surface at the bottom, for x2 damage.

A Size -8, half-ounce mouse falls at a tv of about 40 mph. Although he has only 0.5 HP, mass divides impact damage by about 70. Damage will be (4d x 2 / 70) - 0.25, or 0.15 damage – minor injury.

A big Size -5, one-lb. rat hits tv of about 75 mph. He has 2 HP. Damage is divided by about 12 for mass. Damage is (7d+2 x 2 / 12) - 1, or serious – possibly fatal – injury.

A 150-lb. human hits tv of 125 mph. Damage of (12d+2 x 2 / 1) - 5 will be deadly, barring a miracle with a low damage roll and good HT.

A Size +2, 1200-lb., HP 20 horse hits tv of about 160 mph. Mass multiplies damage by almost 3. Damage of (16d x 2 x 3) - 10 is obscene. "Certain death" doesn't do the scene justice; you'll be lucky (?) to find most of the pieces of horse.

The results match what Prof. Haldane had to say about falling critters, though one can only hope that he didn't actually playtest his assertions.

Falling Objects


When something falls on you while you're on a solid surface, use the earlier rules for collisions with nowhere for the target to go. A falling safe will damage you based on its mass, speed, and hardness. Damage results won't necessarily match those from BS rules!

Nice catch

Can you catch a person falling from above? Make a GM call based on guess or cinematic effect. But if you want a technical answer, try this:

You can break the fall of a falling object by doing just the reverse of throwing it. In other words, compute the speed at which you could throw the object – throwing speed, or Ts – from Book 4 rules. (Note that with heavy objects, two arms will serve much better than one.) Reduce the speed of impact by Ts yards per second (or Ts x 2 mph).

Remaining impact hits you as a falling object. You're probably softer than the concrete under foot; even if you can't significantly slow a falling person with a proper catch, you can cushion his fall with your own body and share the burden of ruptured organs.

Advanced Rules

No real additions, just the formulae behind falling time and distance:

For Lightning Calculator GMs, the distance an object falls in a given length of time, ignoring air resistance, is equal to

distance in yards = 0.5 x acceleration x time^2

where acceleration is about 10 yards/sec/sec in earth gravity and time is measured in seconds. Or solving for time:

time in seconds = square root of (2 x distance / acceleration)

Miscellaneous Hazards

Poison and Drugs

A "dose" of poison is usually expressed in terms of what it does to a normal human. How to adjust effects for the target's size depends on the poison.

Poison gas or spray might use the exposure hazard rules to modify damage. It'll be very lethal to small creatures – precisely what we love about bug spray.

A spray or other contact poison is affected by notes on jets above. Cube-square effects apply, but the "dose" also has a given maximum size. If you're so small part of the dose "misses" you, adjust damage accordingly.

"Generic" internal poisons that cause HP damage will already be deadly to small creatures and easy on large ones, by virtue of HP alone. Additional modification to damage for cube-square effects is reasonable, but makes effects even more extreme. (Fat characters will be happy to see damage effects lowered under such a rule, though!)

Otherwise, effects are up to the GM. A tiny PC taking a human-sized dose of a mind-altering but otherwise safe drug might suffer only penalties on related HT rolls, as per exposure hazard rules – or might suffer massive damage from overdose. Effects will never be certain. In an infamous episode, psychologists once took a dose of LSD with mild effect on cats and scaled it appropriately for testing on elephants – but instead of light tripping, the pachyderms convulsed and died. Try explaining that mess to your grant patrons.


Like poisons, there are too many types and effects to deal with in detail. In general, smaller creatures will succumb more quickly, large ones more slowly. Simply applying flat damage to HP certainly gets that effect, though to an extreme: a 2" PC would succumb to a damage-causing disease about 36 times faster than a human PC.

You get a milder effect by using exposure hazard rules. Multiply damage by Linear Scale to represent the amount of disease-causing agent the body size is able to contain, then apply cube-square effects. A 2" PC will succumb to a damage-causing disease about 6 times faster than a human.

For effects based on HT rolls, see the exposure hazard rules for notes on size. But whatever the rules say, adjust the effects of disease to what you think is right for a given character's size and shape.

Internal Injury

Heart attack

Any major injury to the heart creates risk of heart attack. Let any damage of HP points or greater (including crushing!) directed against the heart force a roll vs HT to avoid a heart attack. This roll is at -4 for HTx2 damage, -8 for HTx3 or greater damage.

Failure means a minor heart attack. Failure by 4 or more or a critical failure is a major heart attack, and failure by 8 or more is fatal. Minor heart attacks do 2d damage and stun you (roll HT each turn to recover; a critical miss brings on a major attack). Major heart attacks do 6d damage and incapacitate you. Multiply damage for either attack by your Linear Scale, so it's appropriate for your size.

Make a HT roll for crippling if you survive a major heart attack. Failure leaves behind (1dx5) points of physical or mental disabilities.

See Book 5 for more on the heart as a combat target and Book 3 for the Weak Heart disadvantage.

Acceleration and Gravity


Rules for the stresses of sudden acceleration and deceleration are on CII p. 131. Add your Half modifier for natural encumbrance to HT rolls – small creatures will stand up well to acceleration, large ones poorly.

Note that these rules cover the effects on acceleration on miscellaneous internal systems; effects on mobility are a different matter, handled by your WSR and Book 2 rules. Also note that the rules are for sudden or changing acceleration or high-speed maneuvers; constant acceleration is easier, with effects no different from those of gravity.


High gravity should induce the systemic effects described under acceleration, in addition to the effects already given on CII p. 141. See the p. 131 notes on constant acceleration: a character on a 6-g world will roll HT each hour to avoid stunning or worse. (That'll be the least of his worries if he's being physically crushed by his weight too: see Extreme Encumbrance in Book 2.)

Bright Lights

Below is an attempt at a master rule for too dark – and too bright – conditions:

Light Level Table

light level





Flash attack


-8 Vision, -4 DX and IQ

searchlight in face


-4 Vision, -2 DX and IQ

police interrogation

Very bright

-2 Vision, -1 DX and IQ

bright sunlight; sun in eyes


no penalties

sunny day


no penalties

shade, cloudy day, bright indoor light

Slightly dim

no penalties

ordinary indoor light


-1 darkness penalties

dim indoor, bright firelight

Very dim

-2 darkness penalties

dim firelight


-4 darkness penalties


Very dark

-8 darkness penalties


Total darkness


no light



Each level of light beyond "generic" Blinding slaps -2 on related HT rolls and doubles duration of blinding.

Bad Sight (light sensitivity) from Book 3 boosts the brightness of slightly dim or brighter light by two levels. Mild light sensitivity boosts the same brightness by one level.

Night Vision removes penalties for any dark light, except total darkness. A more realistic 5-point version from Book 3 halves penalties, i.e., reduces darkness level by 1 between slightly dim and very dark. Night Blindness from Book 3 increases the same darkness levels by 1.

Sunglasses reduce light level by 1; heavy wrap-around dark goggles or welder's goggles reduce levels by 2. Yes, this means they'll only make you blinder in dark rooms.


Everyone knows normal human night vision takes time to "warm up". Treat a dim room as a level or two darker for a few seconds when the lights suddenly go out.

Try running a fight outdoors with a bright sun low in the sky. Two fighters will each maneuver to keep the sun in the other's face.


GURPS' treatment of fatigue is a favorite complaint among GMs. Online debates go round and round over whether to replace ST with HT in the fatigue rules. Unfortunately, these discussions usually go nowhere useful.

The first trick to solving things is to get terminology straight. GULLIVER will use "Fatigue" (capitalized) to mean the pool from which points are lost; "fatigue" (uncapitalized) are these points. It's perfectly analogous to "Hit Points" and "damage". And yes, it is odd to use "Fatigue" for what should probably be called "Energy" or "Stamina" – Fatigue is quite the opposite of fatigue. But the words are part of the game. Capitalization should keep things clear in this discussion.

The second trick is to realize that Fatigue can be based on either ST or HT – you just need to fill in the missing parts required to make either one work. Below is an attempt. Pick one of the two systems and stick with it.

General Fatigue Rules

The following rules cover fatigue issues for either method of basing Fatigue:

General causes of fatigue: Apply fatigue per BS p. 134.

ST loss: Per GURPS, don't bother recalculating damage or encumbrance as ST is lost to fatigue; it's a hassle. (In a very detailed game, you could do so without too much trouble by re-calculating stats only for predetermined lowered ST cutoff points.)

Movement: GURPS rules base fatigue for marching, battle, and overexertion on the amount of time engaged in the activity. The same should go for running, swimming, or flying: take a point of fatigue every 20 seconds, not every 100 yards.

Walking, slow swimming, and slow flying are the equivalent of marching, costing a base 1 fatigue per hour. A fast walk or jog will cause fatigue at a rate between that of marching and running: 1 point per minute for a fast jog, 1 point per 10 minutes for a slow one.

Sprinting costs 1 fatigue every 10 seconds.

Here's the Table from Book 4:

Move and Fatigue Table

Move is greater than...

up to...

type of Move

fatigue interval



slow ("walking")




brisk ("jogging")

10 minutes



very brisk ("fast jogging")

1 minute



fast ("running")

20 seconds


x1 + Sprint bonus


10 seconds

x1 + Sprint bonus


Extra Effort sprinting

1 second

Extra Effort: Extra Effort, whether in sprinting or any other activity, costs 1 fatigue per turn. See Book 4.

Heat: In a hot environment, add a point to any fatigue assessed; add twice that much if very hot weather or if in hot clothing or armor. Decide what "hot" is for a given creature, based on its temperature comfort zone.

Lack of sleep: The GURPS rules are arguably too harsh on physical power. Try 1 fatigue for a half night of lost sleep instead, 3 fatigue for a full night – but with an automatic -1 DX/IQ per point lost. Alertness definitely suffers along with IQ, or possibly even more so.

Will suffers too, and Will rolls may be necessary to avoid falling asleep at inopportune times. But a Will roll may also allow you to halve the DX/IQ penalties for a short time.

A night of lost sleep adds Bad Temper to most people, and possibly Absent-Mindedness. Severe sleep deprivation can cause hallucinations or worse problems.

Non-ST losses: There's a lot of emphasis on loss of physical strength from fatigue in GURPS, and not enough on loss of other capacities. Let a drop in Fatigue to ST x2/3 or less cost you -1 DX and IQ. Fatigue of ST x1/2 or less means -2 DX/IQ, and Fatigue of ST x1/3 or less means -3 DX/IQ. These penalties affect skills, and may be applied to Will or other rolls as well.

Magic and psionics: How to handle fatigue from magic or psi is a tricky topic. See Book 8.

Recovery: Recover Fatigue at a rate of Fatigue x1/10 points per 10 minutes of rest. That lets Reduced/Extra Fatigue play a role in recovery rate. Recover related lost capabilities as appropriate. Any fatigue and penalties from lack of sleep require sleep to cure.

The rules still allow no role for HT in recovery. To fix this, double recovery rate per full 5 points of success on a HT roll; halve it per full or partial 5 points of failure.

Encumbrance and Fatigue

GURPS has simple notes on how encumbrance affects fatigue from physical activities. Below is an extended system:

Physical activities

Ignore encumbrance notes on BS p. 134. Instead, divide base fatigue for physical exertion by your Move Modifier for encumbrance. That means x1/2 normal fatigue for a run or climb at Negative 4 encumbrance, x5 at X-Hvy, and so on.

That's the same as multiplying the relevant time period by Move Modifier: 1 fatigue per 2 hours for a march at Neg 4 encumbrance, 1 fatigue per 0.2 hours for a march at X-Hvy, etc.

For reference, multipliers for positive encumbrance are: x1.25 for Light, x1.67 for Medium (or use x1.5 for simplicity), x2.5 for Heavy, x5 for Extra-Heavy, and x10 for Super-Heavy.

Fighting gravity

Land: There's no fatigue cost for standing there, although Super-Heavy encumbrance from weight is a special case: you suffer 1 fatigue per turn, as GURPS suggests, just for standing still! (Sitting or lying down may alleviate this fatigue.)

Air: Gliders are in free fall and don't spend energy on moving forward or fighting gravity. Treat gliding as similar to walking (marching), for the low effort involved in maintaining gliding pose and adjusting course. The shortness of glide times makes fatigue a moot point anyway, unless you can soar for hours.

It's a different matter for powered fliers. Use regular fatigue for movement: running fatigue for fast flight, marching fatigue for a slower pace, etc. But in addition to fatigue for movement, apply 1 fatigue every 5 minutes for the effort to stay airborne.

Adjust this extra fatigue for encumbrance as above. But use encumbrance from aerial WSR only, not MSR – this is fatigue from fighting gravity, not moving mass forward. (At Super-Heavy encumbrance from WSR, pay 1 fatigue per turn to stay level.)

Example: You have MSR 4. In flight your WSR is 20; aerial MSR is 4, x 4 for Encumbrance Factor = 16, for Neg 2 encumbrance and Move Modifier x1.2.

Fatigue for movement ranges from nothing for holding still, to march fatigue for slow movement (1 fatigue per 1.2 hours), to running fatigue for fast movement (1 fatigue per 20 x 1.2 = 24 seconds).

But on top of that is a cost for remaining airborne, regardless of forward movement. Read across from WSR 20, to get Move Modifier x3/5: you burn a constant 1 fatigue per 5 x 3/5 = 3 minutes to stay airborne, separate from any fatigue for movement.

A design built with airfoils (see Book 3) may have WSR 0 in air if moving forward quickly, and thus no fatigue cost for fighting gravity. But their lift varies with speed, down to none at all when hovering. Hovering is exhausting, or simply impossible, for most birds.

Water: Swimmers usually have neutral buoyancy and can float suspended for no fatigue cost, but those with a positive or negative WSR will have to fight to stay level, and will suffer fatigue as flapping birds do: fatigue for movement plus fatigue for the effort to resist sinking (or floating).

Carried loads

Loads of carried stuff cause fatigue from normal encumbrance, as above. But make exceptions for special cases, such as a load hoisted above your head, a bowling ball held at arm's length, etc. Even if your overall encumbrance level isn't great, you'll be burning energy fast.

Recalculating encumbrance

Recalculating encumbrance whenever ST drops due to fatigue is realistic, but forget about it. Like recalculating weapon damage, it would slow play.

However, it might be fun in a drawn-out two-character duel. You can also recalculate encumbrance in the case of illness or other chronic fatigue; that lets you determine exactly how slowed and "bedridden" a weakened PC would be. A person can easily be immobilized by his own weight if he's suffering reduced ST from disease or fatigue.

Basing Fatigue on ST

This is the standard GURPS method, villified by many a GM but workable with a little fixing up:

Base Fatigue

Set Fatigue equal to your Combat ST. The method makes sense: if fatigue is a loss of physical strength, then of course ST represents the pool from which it's lost.

Load ST should suffer from fatigue too, at a proportional rate if it differs from Combat ST. Either can act as the "base" for Fatigue; GULLIVER arbitrarily gives the job to Combat ST.

Modifying Fatigue

High levels of ST in GURPS cost very little per extra point. Extra or Reduced Fatigue should always be worth less than incremental ST. Reduce the value of incremental Fatigue to half that of incremental ST, when the latter is worth 5 points or less.

Gaming Fatigue

Fixes for problems with ST-based Fatigue as presented in GURPS:

Energy use and fatigue: This is the big one. Loss of Fatigue should in many cases correspond to energy expended; this isn't represented in GURPS.

The all-important rule:

For most physical exertions, multiply points of fatigue by Combat ST x1/10.

That is, a point of fatigue equals 10% of your Combat ST. Apply that rule to all of the above – where the rules say "1 fatigue" from physical exertion, multiply that point by Combat ST x1/10.

This applies to all physical exertions. GURPS applies flat fatigue from a long run or night without sleep to all creatures equally – meaning a dinosaur feels nothing, a cat is wiped out. By applying fatigue equal to 10% of Combat ST, a cat and brontosaur properly use vastly different amounts of energy to run, fight, or put off sleep.

Accounting for ST loss: As you lose Fatigue, lose ST in the same proportion:

Example: You have Combat ST 20, and thus Fatigue 20. Where the rules say to suffer 1 fatigue from running, fighting etc., you suffer Combat ST 20/10 = 2 fatigue.

You lose ST in the same proportion as you lose Fatigue. If you lose 50% of your Fatigue, lose 50% of ST. For Combat ST, that's simple, as it equals Fatigue – cut Fatigue from 20 to 10, and you cut Combat ST from 20 to 10. But if Load ST is, say, 40, then it drops from 40 to 20.

Note that if you have Extra or Reduced Fatigue, Fatigue does not equal Combat ST. You still lose ST in proportion to Fatigue loss: if you have Combat ST 20 and Load ST 40, but Fatigue 24 thanks to Extra Fatigue, then a drop in Fatigue by 50% from 24 to 12 cuts Combat ST by 50% from 20 to 10, and Load ST by 50% from 40 to 20.

In any situation, it might be best to keep things simple by using a few cutoff levels, such as x2/3, x1/2, x1/3, and x0. Don't mess with ST until Fatigue drops to those cutoff levels, and then cut ST to the same level.

Accounting for HT: This is a pretty big oversight in GURPS: there's no role for HT in fatigue rules! To fix it, roll HT every time you apply fatigue. Success halves fatigue; each full 5 points of success further halves fatigue. Each full 5 points of failure doubles fatigue.

In general, this rule will slow the rate of Fatigue loss, relative to the GURPS standard.

Working the Fatigue 3 rule: That's the point at which you slow down from exhaustion. But small creatures will start out with Combat ST and Fatigue of 3 or less, making the rule invalid.

The fix is easy: Cut Move and Dodge in half when Fatigue is reduced to Combat ST x1/3, rounded down. You collapse when Fatigue reaches Combat ST x1/10, and pass out at Fatigue 0.

Note that with Extra Fatigue, you'll have more "give" before Fatigue drops to Combat ST x1/3 level. With enough Reduced Fatigue, though, you could find yourself permanently exhausted!

Basing Fatigue on HT

This is a favorite method of many gamers. It's not inherently any more correct than the ST-based method, but is arguably easier to play, with fewer adjustments needed:

Base Fatigue

Set Fatigue equal to your HT. Any Fatigue stat – 8, 13, whatever – is equally valid for a creature of any size.

Modifying Fatigue

Buy Reduced and Extra Fatigue at their normal cost; the cost of ST doesn't matter.

Gaming Fatigue

A few things work automatically under this method, with no further adjustment.

HT is automatically accounted for in loss of Fatigue.

You don't need to multiply fatigue by energy expended (i.e., by Combat ST x1/10); subtracting a straight 1 fatigue from Fatigue works fine for any creature.

The Fatigue 3 rule works fine. Halve Move and Dodge at Fatigue 3, collapse at Fatigue 1. This absolute number works for any creature, whether mouse or brontosaur.

One issue remains:

Accounting for ST loss: You'll need to reduce physical power as fatigue accumulates. Simple proportions work: if you lose X% of your Fatigue, you lose X% of your Combat ST and Load ST.

To keep it simple, though, use a few cutoff levels, such as x2/3, x1/2, x1/3, and x0. Don't mess with ST until Fatigue drops to those cutoff levels, and then cut ST to the same level.

Care and Feeding of Giants

How much would a Leprechaun or Giant eat? How much air does a mouse need? Given the vagaries of metabolism and respiration, the only answers here are default requirements for game purposes:

Food Requirements

Your default food requirements are the same as a human's requirements, times your Area Scale. That's for a simple rule; use a multiplier of (Linear Scale)^2.25 for a detailed rule, or (your mass/150 lbs.)^0.75 for an advanced rule. The latter most closely matches measurements made of mammals, and takes individual weight into account.

That sets requirements relatively high for small creatures. With lots of surface relative to mass, they have to make up for heat loss by burning lots of fuel. Big creatures hold in heat well, so burn less fuel relative to mass. (It's been said that if a cow burned fuel at the same rate as a mouse, relative to body mass, its body temperature would exceed the boiling point of water!)

Take a 2" PC as an example. Instead of a human level of, say, two pounds of food, he might eat one-thousandth that amount per day. Of course, although he's eating only two thousandths of a pound of food, he only weighs four or five thousandths of a pound! A small mammal or bird with a higher metabolism will eat even more in a day, perhaps more than its own weight!

Further adjustments

Metabolism: It's up to you whether to additionally adjust default requirements for perceived metabolism. If so, try multiplying requirements by (Basic Speed/5), or the square root of that for a less pronounced effect. Also consider adjusting upward or downward for unusually high or low Load ST.

Diet: Default requirements are for omnivores or eaters of seeds and fruit. Halve for carnivores, double for grass-eaters. Grass is much easier to come by than meat, but is lower in energy.

Activity: Base requirements also depend upon activity. As a rule of thumb, multiply by x1.25 for high activity (hard manual labor), x1 for mixed activity (a good default for adventuring), x4/5 for low activity (white collar lifestyle), x2/3 for minimal activity (very sedentary), and x1/2 for near inactivity (staying in bed). Most of us modern types live at the low activity level or worse, which is why we eat too much.

Daily intake can be impressive when you're both physically active and bulking up. A good, stout sumo wrestler can eat 4 times as much as his average countryman. Dinner alone is said to top 3600 calories, the equivalent of six or so Big Macs!

Cold-blooded: Cold-blooded creatures can cut requirements greatly when inactive from cold. For an advanced rule, further cut cold-blooded requirements to x1/5 that of warm-blooded creatures when at rest, and x1/2 when mildly active. Requirements are as high as those of warm-blooded creatures when fully active.

Customizing: The above only provides a default for game purposes. Adjust for a design or gameworld: if you rule that the PC microhumans have the same requirements as a proportion of body weight as humans do, then they do. Explain it as a fact of more efficient metabolism, or thick fur that retains heat well. Or don't bother explaining it at all.


However you adjust things, the defaults you establish for any given size are part of the GULLIVER Size trait. If you're not using that, decide for yourself how many points a given size's default requirements are worth.

Non-default requirements for individual characters or races, on the other hand, use Decreased/Increased Life Support to adjust amounts and character cost. These will be fairly common traits in creature designs. Many desert creatures, from rodents to camels, have unusually low metabolic rates and food requirements (a useful adaptation in a desert!). Seals and whales have unusually high rates, no doubt related to maintaining body heat in cold waters. Shrews have bizarrely high metabolic rates, with three times expected oxygen consumption while at rest.

See Book 3 for lots more on eating, metabolism, and temperature regulation modifications.


How many meals per day your diet divides into is up to your physiology and custom. Large-mouthed creatures may gulp it all down in one meal. Those with small mouths, or who eat small things, may spend lots of time at the table.


Miss your food requirements, and you run into trouble. The rules below only look at Fatigue and HP loss, but using the earlier detailed Fatigue rules will bring other penalties into the picture. The GM can be creative with other debilitating effects of starvation, even long-lasting effects.

Note that a starving character will probably lower his level of activity, reducing his need for food (above) and delaying the worst.

Simple rules

Start with the GURPS starvation rules on BS p. 128. Let a "meal" for these purposes be one-third your daily food requirement, whether that's a sit-down meal or not; loss of each "meal" results in 1 fatigue.

Handle fatigue using the rules in this Book; remember that fatigue will be proportionate to your ST if you base fatigue on ST.

Once Fatigue is reduced to Combat ST x1/3 or less (or just Fatigue 3 if you base the stat on HT), you start to lose HP instead of Fatigue, at the rate of HP/10 points per three "meals" missed. (That slows death by starvation quite a bit compared with GURPS rules; humans can survive for weeks without food, albeit in a miserable state.)

Detailed rules

As above, but with fatigue levels for non-eating adjusted for food requirements. Unfortunately, the calculation isn't simple. Earlier rules told you how much food you eat relative to a human. Divide that by your weight relative to a human (i.e., divide by (your weight/150 lbs.)). Take the square root of the result. What's left over is a multiplier for any fatigue or damage from starvation. Small, active creatures can starve fast!

You can forego the calculations and eyeball the number as 1 / (the square root of your Linear Scale), if you don't want to be too exact.

Example: A 2" humanoid eats a fair portion of his body weight in food per day; going without that huge fuel dump is a lot harder on him than missing three modest meals is for you. He suffers roughly 6 times the relative fatigue from a day of fasting.

Advanced rules

As if the above weren't enough, you can consider the role of fat too. Such a system might use a separate pool of "virtual Fatigue" equal to Fatigue/2 for normal weight, Fatigue for Overweight, Fatigue x1.5 for Fat, and Fatigue x2 for Obese. Skinny gives you nothing.

You suffer fatigue and HP loss normally from starvation, but once in a while loss is applied to the virtual Fatigue pool instead. Loss to health relative to loss of the virtual pool depends on how severe the food deprivation is; HT rolls might also let you divert more loss to the virtual pool.

Safe dieting would leave normal Fatigue a little depleted (hence the discomfort), and slowly reduce the virtual pool. Chronic under-eating would keep normal Fatigue very low, but the virtual pool might absorb what would otherwise become HP damage. Very little or no food will cause dangerous fatigue and HP loss as usual, but every third point of Fatigue or HP loss might be absorbed by the virtual pool instead, prolonging the inevitable.

The character's weight status changes appropriately as the virtual pool depletes. When it's gone, he's Skinny; no more fat to help out. But that's all just a bunch of sketchy notes; fleshing out the system is left to the enterprising GM.

Recovery from starvation

HP loss from starvation recovers in the usual manner if full rest and food requirements are available. Fatigue loss from starvation should recover more quickly, maybe a point every two hours if you have full rest and food – but it won't recover completely until health does. A suggestion: if you're down 20% HP from starvation, your Fatigue can only recover to 10% down from full; if you're down 50% HP from starvation, Fatigue can only recover to 25% down from full; etc.

Water and Air Requirements

Assume base water and air requirements scale in the same way as base food requirements, for no cost; again, Decreased and Increased Life Support let you modify things.


Dehydration rules can follow starvation rules, but the condition is more severe. Suffer fatigue as above and take HP/10 damage per missed "meal" (one third daily requirement) of water. At zero Fatigue you become delirious or unconscious; HP continues to drop until death.

Remember that hot weather increases requirements per BS p. 128. If you use the complicated stuff from the detailed starvation rules, you'll take more damage when you miss those higher requirements. Increase any fatigue and damage from dehydration by about 25% in hot weather, 50% in the desert.


There are GURPS rules for suffocation on BS p. 122. Leave it at that, without modifications for requirements relative to weight, etc.; the only change here is that fatigue will be adjusted for ST if you base Fatigue on ST, as per Fatigue rules introduced earlier.

Book 3 introduces a new Reduced Air Requirements advantage that lowers or does away with air needs.

Life Span

Aging is an inevitable hazard for all natural creatures. Life span varies drastically among organisms; it's greatly dependent upon metabolic rate, which in turn is affected by size.

Estimating Life Span

Size and life

If you want a pseudoscientific way to guess at your creature's allotted time, limited data exists comparing life span with mass in mammals and birds. In these studies, life span scales roughly with the square root of Linear Scale (or more exactly, mass to the one-fifth power).

For game purposes, take a base 50 years and multiply by either the square root of your Linear Scale, or by a more accurate (mass in lbs. / 150 lbs.)^0.2, as you prefer. The result is what GURPS calls the onset of aging (i.e., the point at which you start making regular rolls for loss of attributes). Multiply the intervals between aging rolls in the same way.

The calculation works for birds, humans, and presumably sentient humanoids in general. However, these have unusually long life spans for any given mass. Divide the result by 2.5 for other mammals.

Metabolic rate and life

If you want more of a metabolic rate factor worked in, multiply by the square root of (5/Basic Speed). That'll extend lifespan for sloths and slow it down for hyped-up predators. But whatever your result, adjust things as you like; any given creature's life span can vary drastically from that prediction. Take your final life span and buy the traits you need to go from default human life span to that of your design.

Interesting tidbit: Frequency of heartbeat and breathing in mammals are said to scale with body mass in (roughly) the inverse of the way lifespan scales with mass. The result: elephants and mice have lives of about the same length – not in years, but in number of breaths and heartbeats!

Cold-blooded: All bets are off for cold-blooded creatures; they have no base metabolic rate determining life span, but rather one that varies with the environment. For an unscientific game workaround, use the life span calculation for a mammal but multiply by 2 for a cool environment, 1.5 for a temperate one, 1 for a hot one. Detail-loving GMs will further take game time spent hibernating or semi-frozen, and apply only a portion of it toward character aging.


For game purposes, life span modifications are not part of the effects of the Size trait. Humanlike life span is the default for all PCs, and any nonhuman life span has a cost.

Make up your creature's life span or play with calculations as above. If it's shorter or longer than the human norm, buy Extended Lifespan, Short Lifespan or other traits (see Book 3) as appropriate, to arrive at a cost for the lifespan you've determined.


One note on aging: when an aging roll indicates the loss of a point of ST, multiply that loss by your Linear Scale (or Area Scale for Load ST). Likewise, when you lose a point of HT, lose HP at the rate of (1 HP x Linear Scale). This adjustment properly accounts for a creature's scale.


1. Die, Monster, Die!

A fierce dragon finally meets its match: Conrad the Bavarian, who takes the dragon down from 120 to 0 HP and goes to administer final rites. Good job, but one question: how long will it take to deliver another 120 points to kill the unconscious wyrm? Or 240 points if the beast makes a couple of HT rolls? Up to 600 points if those HT rolls keep succeeding? (Dragon HT can be pretty high!) Won't the magic-user, the thief, and the cleric have nabbed all the gold pieces by the time Conrad finishes hacking away?

Well, if your character managed to chalk up 120 points of damage against a spitting, smoking terror, working another few hundred points against a barely-breathing lump shouldn't be that hard. There's always the "instant death" rule, but even if you decide to play out the gore, things should be quick. Conrad can place his sword point-down on the fallen beast's head, place all his weight on it, and make like he's digging. That could be gamed as maximum damage, which seems fair for a carefully aimed hit against an unresisting target. Add damage for an All-Out Attack, plus some for Conrad being able to put his weight into it (see Book 5). The brain hit allows a x4 damage multiplier. Once the sword gets past the skull's DR, the GM can allow additional "attacks" that ignore DR, as Conrad twists and shoves that sword... Not pretty to play, which is why there's an "instant death" rule, but finishing the dragon definitely won't take all day.

Still, the sight of big, dumb monsters falling into unconscious slumber just like the heroes do, instead of up and dying like good monsters should, just isn't kosher sometimes. Monsters should rage and slaver on until the point of death, and then keel over bloodily for good, right? How to game this without going back to the incorrect "death roll at -HT" rule? Suggestions:

Bonuses vs KO

Let monsters fight long after HP 0, like a berserker. A quick'n'dirty rule for non-PCs: For every point of racial IQ under 10, add +1 to rolls to stay conscious. Assume a successful consciousness roll lets the monster stay conscious for as long as dramatic license requires; if the PCs want to force another unconsciousness roll, they'll have to inflict fresh, significant (HP/10 or more) damage, and not hide in a cave counting down the seconds until a missed consciousness roll.

The drawback to this rule: it makes fighting monsters more dangerous!

Reduced KO zone

Give monsters a smaller range of "below-zero" HP for death purposes. For non-PC races with IQ under 10, multiply this HP by (IQ/10), i.e., x0.3 at IQ 3, x0.7 at IQ 7, etc. If the dragon has IQ 5, it would have normal HP between 120 and 0, but would make a death roll at only -60 HP and every -30 HP thereafter. A HP 120 giant worm with IQ 2 has full HP above 0 but makes death rolls at -24 HP and every -12 HP thereafter.

The explanation? Game balance, plain and simple. Well, you could mumble something about simpler nervous systems and the ability to support the unconscious state... but more importantly, the effect is nice.

However, there's a drawback: monsters become considerably weaker!

Combined approach

Give monsters both the above: bonuses to stay conscious at HP below 0, and the smaller below-zero HP score for death purposes. This combination almost ensures that a dumb, drooling monster will raise full-blown hell right up until the hero's final sword stroke.

The quicker death rolls are a major downer from the monster's point of view – but a knockout is death anyway in mortal combat, so the consciousness bonuses balance it out. You could even allow this option as a zero-point trait for a low-IQ, nonhuman PC race!

2. New Damage Options

Here are two rules options: a reworking of the Toughness trait, and a reworking of ST-based damage. While they're only offered here as curiosities and are not used througout GULLIVER, either option has nifty benefits in play – and they work even better when used together.

New Toughness Trait

You can rework the GURPS Toughness trait to represent your resilience from thick muscles: you'll shrug off punches, yet a knife will hurt you. That makes it useful, but decidedly different from DR. (Players of Hero System games will be reminded of Physical Defense.) It's different from old GURPS Toughness too; just forget about that trait (or call it "Rubbery DR", which is what it is). This new Toughness is a brand new thing.

The basics: Divide your Combat ST by 5 and round down. That's your Toughness. It's completely free for any creature.

When you're hit for damage, follow standard GURPS procedures: subtract DR and multiply the remaining damage for damage type and location.

Now subtract Toughness from damage, but only up to the basic hits before multiplications.

In other words, there's no protection against the extra damage caused by cutting or impaling wounds; those hits are always taken as injury. Your Toughness protects as well as DR does against punches and falls, but less so against a slash or stab, and much less against a stab or a bullet hitting vital organs. Try some numbers and see:

Example: You have ST 16, with free Toughness 3. You shrug off a punch of 3 or less damage. A punch for 5 points of damage inflicts 2 points on you.

Example: Razk the Evil Lizardman has DR 1, and Toughness 3 from his ST 15. You punch Razk for 5 damage. He takes only 1 point (5 minus DR 1 minus Toughness 3 = 1 damage).

You make a 5-point thrust with the sword. That's 4 basic hits after DR. Multiply by 3 for vitals: 12 damage. Razk's Toughness absorbs only 3 points; one of the 4 basic hits gets through, as do all 8 hits of extra impaling damage.

You now deal a 9-point sword slash, reduced to 8 basic hits by DR. Multiply by 1.5 for cutting; that's 12 points for Razk to deal with. After Toughness, he takes 9 points of damage.

Even a lowly 3-point cut, reduced to 2 basic hits by DR, will hurt. Damage looks to be 2 x 1.5 = 3 points of final damage before Toughness. But Razk's muscles stop no more than basic hits, or 2 points in this case. The extra point of damage for cutting injures Razk no matter how much Toughness he has.

Note that Toughness doesn't protect vs poison or disease – just whacks, stabs, pokes, falls, and so on.

Toughness and shock: How you handle shock with this Toughness is up to you. The first option is to keep shock as damage times some multiple – meaning that if Toughness absorbs all damage, then there's no shock.

The other option is to calculate shock as damage before Toughness, times the appropriate multiple, and then subtract Toughness from Shock. That's a little more complex, but allows attacks against vital targets, or other high-shock attacks, to inflict shock even when Toughness shrugs off actual injury. In many situations, it's a realistic effect that GURPS players like.

Cost: This reworked Toughness is less useful than DR. Extra Toughness above the free amount should cost less than DR. One option is x2/3 the cost of DR.

Another great method is to price Toughness at some flat cost, such as 7 points per level. GURPS' 3-point cost of DR becomes the cost to convert a point of Toughness into DR. That means once you've converted all your free Toughness into DR, buying more DR means you'll have to buy more Toughness and pay to convert it to DR.

That puts a limit on cheap, 3-point levels of DR in the game; once an alien race converts all its Toughness into DR, additional DR will cost 10 points per level (7 points to buy another level of Toughness, 3 points to turn it into DR). That's good news for the many players of GURPS who find DR too cheap in the game.

Final note: ST gets cheaper and cheaper as it gets higher (under either GURPS rules or the nifty new suggestion for ST costs presented at the end of Book 1). When the cost of ST drops below 10 pts per level, adjust the cost of additional Toughness accordingly. Price Toughness at x2/3 the cost of additional ST, and charge x1/3 the cost of additional ST to turn a level of Toughness into DR.

Extra detail: Halve Toughness in the hands, feet, groin, throat, and nose. You've got less flesh and muscle there to protect delicate stuff. The eyes have no Toughness, and the brain has DR instead of Toughness. Any location with low Toughness becomes a tempting target for foes!

Caution: The Toughness rule offers benefits besides its realism. Players sinking points into high ST become much happier with this rule – both for the free Toughness they gain, as well as the increased importance of their damage scores in overcoming foes' Toughness. (The difference in damage dealt by a ST 15 punch vs a ST 10 punch is greatly magnified when a foe's Toughness subtracts 2 or 3 from that damage.)

But there's a drawback too. The rule messes up combat balance, lowering the effects of all damage rolls. In GURPS, ST 10 fighters with 1d-4-die punches can hurt each other (somewhat slowly, making good rolls), but give them Toughness 2 and their punches won't hurt each other at all unless All-Out Attacks, damage-boosting skills, or delicate body targets come into the fray.

That's fine if you prefer that effect, but you'll have to raise damage levels if you want to restore the original GURPS balance. That's where the new ST damage rule helps out:

New ST Damage

Interested in damage scores that scale neatly with ST? Here's a solution:

Basic Damage from ST Table

Combat ST

Thrust Damage
































































The progression is obvious. After a minute of study, you won't even need the Table much – with just the damage from ST 10 to 20 you can find damage for any higher ST. If ST 12 does 1d+1, then ST 72 does 7d+1. ST 122 does 12d+1.

Low ST: Damage scores under 10 fall to their own unique progression; things get a bit hazy down there, just as they do in GURPS. If you want unblemished linear progression that includes weak ST, just divide a higher ST's damage dice by the appropriate amount. For ST 2, roll ST 10 damage and divide by 5.

Swing: Where's the Swing column? It's left out. If you use the Weapon Design System from GLAIVE, you won't need a swing stat! But if you do want one, simply multiply ST by 1.5, and use the thrust for that ST. ST 10 does thrust 1d, swing 1d+2. ST 20 does thrust 2d, swing 3d. And so on.

That establishes a neat, clean relationship between thrust and swing damage, which is a good thing. But it does also mean an extra 50d damage when your ST 1000 hero eschews his punch for a swung police baton.

The Weapon Design System avoids this problem. Otherwise, you need to place some appropriate limit on the extra damage added by a swung weapon. Limit the extra damage from a swing to (square root of weapon weight in lbs.) dice. That means a Super wanting to inflict big extra damage with a swing is going to need an appropriately big, heavy weapon.

Example: A 1-lb. baton inflicts thrust damage with a poke, which means 100d for your ST 1000 hero. For his swing damage with that weapon, use the lower of 150d (from thrust damage for ST 1000 x 1.5) or 101d (thrust damage +1d). The correct damage is 101d.

Caution: Base damage under this rule is higher than in GURPS, messing up combat balance for everyone. Fights will end much more quickly!

That's where the above reworked Toughness rule helps out:

Both Rules Together

A match made in heaven. The damage absorption effects of free Toughness are offset by the higher damage all characters dish out with the new ST-based damage, restoring original GURPS balance for similarly sized combatants.

A couple of niggling points remain. Damage from non-ST physical impacts (like fireballs) is reduced a bit for everyone by Toughness, which you may find good, bad, or irrelevant. Tweak numbers if you like, such as adding +1 per die to damage where appropriate.

And of course, dealing with the Toughness stat, though easy, adds one more number to juggle in combats.

But the combination is fun in play. Give it a try.

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GULLIVER v5.3 (2004.04.12) | Copyright 2004 T.Bone | T.Bone's GURPS Diner