Game design musing: Easiest-ever, zero-math “weight-to-power” factor for characters (GURPS)

The last thing I posted to this site was a book review, and before that, a notice of a Kickstarter campaign. That’s two posts in a row that aren’t overly nerdy (as RPG hobbyist stuff goes).

So I’m overdue to post something really dorky.

You: “Uh, no, that’s okay, you don’t have to, really…”

Say you want to set a weight-to-power ratio, or level of weight-to-ST, however you style it, for characters in your games.

“O-o-o-kay, I think we’ve seen this before, and we know how it goes. This is why we got you those meds.”

Hold on. There are two parts to a discussion:

  1. How to determine some sort of weight-to-power factor (a ratio, a level, whatever)
  2. What to do with that factor

That second is the big thing – and we’ll ignore it. What to do with a measurement of weight-to-power in a character is up to you. Turn a ratio into some sort of level, and use that as a mod to athletic skills and Move. Set a given ratio as a prerequisite for buying some athletic trait. Use the level as a modifier to DX. Use a ratio or level as a loose guideline for setting DX, and nothing more. Whatever. That’s its own separate matter. I’m ignoring it. I am so ignoring it that I won’t even put a name on these ratios or levels or whatever.

I only want to show you a way to set a leveled weight-to-power factor – should you ever want it – that requires no math. None.

“Seriously. Your pills. Are they in this drawer? Or in… and what do you mean, ‘no math’? Even if you have to divide weight by power just once, anything like that, it’s math, so you can’t say… No! I will not be drawn into this!”

Really. No math. GURPS has already done it for you.

“Oh, for crying out… Your meds. Please. Some of us have lives, you know!”

So, say you want some innate weight-to-power factor expressed in levels – an encumbrance-like level or few for ponderous creatures that fight against their weight, and a level or few in the opposite direction for lightweight creatures with power to spare. A sort of “natural encumbrance” thing, by whatever name.

“WHERE ARE YOUR PILLS!? I am so calling Dr. von Holst, right now!”

Let’s also say that you aren’t stuck on exactly how those levels should work – as in, “I require that levels represent these specific weight-to-power ratios”. As long as you can turn a character’s strength and weight into some leveled factor that you can use for [fill in your own intended use], you’re flexible on how it all works out. You’re at least open-minded toward whatever I might suggest here.

But. You do have one big requirement: Deriving these levels for any creature has to be ridiculously simple. No new tables, no calculations, no conversions. Not even “divide your weight by your Basic Lift”. No math.

“Hello? Is anybody… WHY IS THE PHONE LINE CUT!? Dear gods, did you…

Can this thing be done? Yes. It’d be easy to show you in a few seconds, a little fiddly to explain in writing. I’ll break it up into small steps.


1) Pull out your handy old GURPS “Basic Lift and Encumbrance Table”. It’s the only thing you’ll need.

Here’s an excerpt:

2) Find your ST at left. (If you’ve got Lifting ST, add that in as always.)

Let’s take good ol’ ST 10 as our example. There’s its row on the Table.

I’ll grey out unnecessary stuff. We just need those values in the “None”, “Light”, “Medium”, “Heavy”, and “Extra-Heavy” columns.

3) Look at that space between Heavy and Extra-Heavy. I’ll mark it with a dirty fingerprint.

4) That space indicates a weight range (that of Extra-Heavy encumbrance): for ST 10, it’s more than 120 lbs. but not more than 200 lbs.

Hmm, that sounds like a reasonably normal range of weights for a ST 10 person, doesn’t it. So let’s say that if your body weight falls within that “Extra-Heavy” range, you’ve got a “normal” human ratio of weight to power, with no special effects. Done.

5) But what if your weight is below that range, i.e., 120 lbs. or lower? Maybe it falls within the range one “jump” to the left: more than 60 lbs. but not more than 120 lbs. If it does… hey, we could call that one level of weight-to-power factor (in the “light-but-strong” direction).

Or if your weight falls within the range of more than 40 lbs. but not more than 60 lbs.? You need to make two “jumps” to the left… so let’s call that two levels of this weight-to-power factor.

You get the idea.

6) Going the other direction: what if your body weight is above that starting range marked by the fingerprint? You’ll want to look at higher ranges to the right, and count each “jump” to the right as a level of that weight-to-power factor, in the ponderous direction. Easy enough… except… wait, there’s nowhere to jump!

The same problem occurs if you’re making jumps to the left to find a low body weight, but that weight is below the range indicated by “None”: you run out of Table.

You’ll have to mentally “extend” the Table in either direction, as needed. Fortunately, you can do that.

Note that the Extra-Heavy column has a value 10 times as great as the value in the None column. So there’s our key to extending the Table: every new column you add gets a value 10 times as great as the value four columns to the left, or 1/10 as great as the value four columns to the right.

An actual extended Table would look like this:

(Click to show larger)

But I don’t think you’ll feel the need to make a Table like that. It’s easy enough to do in your head or with quickly scribbled numbers on paper.

7) So, to summarize this:

The easiest way to set levels representing a weight-to-power factor in characters is to just borrow the weight levels already set out in the Basic Lift and Encumbrance Table.

If the character’s body weight would fall under Extra-Heavy encumbrance for its ST, that’s a “normal” human weight-to-power level.

If the character’s body weight would fall under some other level of encumbrance for its ST, every level below Extra-Heavy is a level of a light-and-agile ratio, and every level above Extra-Heavy is a level of a ponderous ratio.

Extend the Table in either direction as needed. Each new column to the left of the Table has a value 1/10 the value four columns to the right. Each new column to the right of the Table has a value 10 times the value four columns to the left.

That summary is maybe as short as I can make it. Is it simple? Well, I leave that to you; I think it’s easy once fixed in mind, though fiddly to explain. I do think it’s the simplest method you could come up with, calling for no new tables, and no “divide weight by Basic Lift” sort of stuff. It just checks your weight against the encumbrance levels already sitting on a GURPS table.

(Although… Extending the Table does call for multiplying its weights by factors of 10. You could point to that and call the whole “no math” claim a lie. I leave that to your mercies.)

Is this useful? Again, it’s all predicated on your wanting some level representing a weight-to-power factor. What you would do with that is up to you. If you do have a use for this, start by naming things. You could name levels in the low weight-to-power direction with a word like “Agility”, and levels in the heavy direction with “Ponderousness” or something. Or use a single term like “Heft”: a “normal” human level is Heft 0, levels in the heavy-and-lumbering direction are Heft 1 and higher, and levels in the light-and-nimble direction are Heft -1 and lower. From there, apply Heft as a penalty to traits and tasks where appropriate (so negative Heft becomes a bonus), or as a guideline for setting traits, or whatever you have in mind, as noted at top.

(As one inspiration (?), see the small home-made GURPS supplement I call GULLIVER Mini. It contains an option for levels of power-to-weight ratio calculated through division and a table, with the suggestion that the levels be used as guidelines for adjusting DX, Basic Speed, and Move.)

Okay, done. Just a little something I wanted to get out of my system and maybe play with later. That really wasn’t so… Hey, where did you go, anyway? Are you… What are you doing down there in the cellar? You can’t tunnel out of here!

“Must… keep digging…”

Ooh, digging, are you? Hey, have you seen my new stats for variant combat shovels, including a Folding modifier? Come on up so I can show you! Don’t make me have to go down there…

Header image: Spiderman represents a high ratio of power to weight, and his head-ramming foe – I assume – has a less agile ratio. I guess. The article topic doesn’t readily suggest a perfect image…


  • Maximilian D Wilson

    That’s cool! I was just recently missing GURPS GULLIVER’s ideas on natural/negative encumbrance–I’ve been thinking a lot about preindustrial army logistics and food supply lately, and how GURPS’ starvation rules only really make sense for extremely fit people with low body fat. If I tie starvation penalties to body weight (e.g. you can lose 1 lb. instead of 1 FP until you get down to Extra Heavy Encumbrance body weight) and then use weight ratios for natural and negative encumbrance, then being fat or skinny will have interesting tradeoffs.

    Anyway, cool technique! Thanks for demonstrating!

  • tbone

    I think long ago I idly poked a bit at starvation rules that took into account Skinny/Fat and other factors, but I never developed anything meaningful from that. If you do come up with some detailed food & starvation rules, that’d be interesting to see.

  • Drejzer

    You can’t escape math.
    Math is everywhere.

    But you can escape calculating things, that’s what math is about.

    So you should use more math!

    Admittedly I can’t think of any function that would convert the things we see in that table to nicer representation…

    • tbone

      Does a simple comparison of two numbers to see which is bigger count as math? If so, then my “no math” claim is definitely not correct.

      In any case, I think I agree with you that the article’s little system might better be described as “no calculating”.

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