Monster weights

[Hilary]

So... is there a formula that can determine a monster's (or animal's) weight using it's size category and strength and maybe basic form (4 legged; animal)?

[Greywander]

I've asked a similar question before. Take a look at this thread and see if you can find what something that will work for you: https://forums.giantitp.com/showthread.php?626521-Average-weight-for-each-size-category

But yeah, I'm kind of surprised they don't have something like this already, as it could be important e.g. if you need to lift or carry another creature, or if you have weight-sensitive equipment e.g. pressure plates, elevators, etc.

[Nitrosaur]

For giants I see how tall are they on average on the MM, to see how much bigger are they compared to an average person, dividing their height by an average human, or a model human for their build, using dwarves for fire giants. Then I multiply the average weight of a human with the build of the giant by 16 and by the size diferential, and add or subtract a little bit for it to feel right. That way, a fat hill giant based on an overweight average joe is around 2.000 kg, and a buff frost giant based on an athletic dude is around 4.500 kg. Maybe you could use a similar method for creatures of similar builds between eachother.

Dragons have their weights on the 4e Draconomicon, and up untill gargantuan they are quite accurate, but I feel they are too heavy at that size, so I make them lighter.

[Chronos]

I'm not sure where that factor of 16 is supposed to be coming from. The logical calculation would be to cube the height ratio, so a giant that's twice as tall as a medium humanoid would weigh 8 times as much, and one that's three times the height would weigh 27 times as much, and so on.

[stoutstien]

Never having to deal with stuff like this is one of the main reasons I moved to a bulk system rather than trying to determine the weight of everything.

[Nitrosaur]

I'm not sure where that factor of 16 is supposed to be coming from. The logical calculation would be to cube the height ratio, so a giant that's twice as tall as a medium humanoid would weigh 8 times as much, and one that's three times the height would weigh 27 times as much, and so on.

You are right! I forgot to say why I made giants that way. While innacure, it kinda felt wrong the weigts I got with the correct calculations. An average frost giant for example is twice as tall as an average african elephant more or less, but the giant would have ended up weighing less than half the elephant's weight, by a factor of 16 they end up more or less even, which felt right to me. It could be explained with giants having thicker and stronger bones and muscles, but honestly I wanted giants to feel big, both in height and weight. But you are right, with no ulterior motive, that's the correct way.

[Ettina]

So... is there a formula that can determine a monster's (or animal's) weight using it's size category and strength and maybe basic form (4 legged; animal)?

I don't think such a formula is possible. There's just way too much variation.

For example, you could have a tallish dwarf and an average-height aarakocra be the same height, and with PC rules they could easily have the same Strength despite the dwarf's racial bonus, but they would still have very different weights. Aarakocra are extremely light for their height and build, likely because they've got avian physiological features such as hollow bones.

Another example - firbolg and goliath both have a Str bonus and both have the same height range, but the average goliath weighs 40 pounds more than the average firbolg. (An average firbolg carrying an average gnome = an average goliath in weight.)

I don't think size, Strength and basic form are nearly enough to figure out how much a creature weighs.

[Eric Diaz]

There is no perfect way to calculate this, since, IIRC, if the giant is made of the same materials as humans (flesh and bone), they would collapse under their own weights.

I think cows can get killed if you push them sideways, making them fall from their own weight. Giants would be a lot worse. (which might be an interesting puzzle for the PCs to solve... I'm think AT-STs...)

Dragon's flight is magical, I guess... but I still picture them a bit lighter than other beasts - like birds or maybe pterodactyls.

So... you can probably invent a number you find adequate.

[greenstone]

But yeah, I'm kind of surprised they don't have something like this already

I'm not, as it would be a massive amount of work with little payoff.

Looking at dndbeyond, there are 97 pages of monsters, with 21 per page. There is a lot of doubleups (lots of humanoid NPCs) but that still leaves over a thousand monsters that someone has to work out weights for.

More than that, since some of those monsters are sexually dimorphic.

And it has to be weight ranges, not just weights. All elephants don't weigh the same.

I know it leads to weird things (the 140lb human can grapple a dragon and drag it 20 feet in 6 seconds), but I think simplicity wins here.

[Hytheter]

I'm not sure where that factor of 16 is supposed to be coming from. The logical calculation would be to cube the height ratio, so a giant that's twice as tall as a medium humanoid would weigh 8 times as much, and one that's three times the height would weigh 27 times as much, and so on.

This would be true if the giant had the exact same proportions as the medium humanoid, but I'd say they're likely to be more solidly built and thus heavier.


I'm not, as it would be a massive amount of work with little payoff.

Looking at dndbeyond, there are 97 pages of monsters, with 21 per page. There is a lot of doubleups (lots of humanoid NPCs) but that still leaves over a thousand monsters that someone has to work out weights for.

More than that, since some of those monsters are sexually dimorphic.

And it has to be weight ranges, not just weights. All elephants don't weigh the same.

I know it leads to weird things (the 140lb human can grapple a dragon and drag it 20 feet in 6 seconds), but I think simplicity wins here.

So you're willing to simplify to the point of innacuracy when dispensing with creature weights altogether, but when trying to put a number on it suddenly you have to account for sexual dimorphism and variance within a species? It could well be enough to provide ballpark figures based on creature size, maybe add some toggles, and let DMs fine tune from there if desired. "A large creature weighs 500lbs, double if it's wearing armour." Done.

[DwarfFighter]

The 3.5 SRD lists weights for a number of monsters, e.g. a Hill Giant is 18 ft. tall and 5.000 lb.

I guess those numbers are as good a starting point as any.

-DF

[Chugger]

What weighs more: a horse or a rhinoceros?

Trick question, because there are 4 kinds of rhinos and zillions of types of horses.

But there are several types of draft horses that can weigh more than a black African rhino (smallest white african rhinos are all pretty much heavier than any horse). And a black rhino is pretty respectable - and will kill you if it can (they can get grumpy). So I think it's pretty crazy that any horse can be bigger than one of the larger types of rhinos - but of course, not the largest type of rhino, which makes sense).

At 3,300 or so pounds, the heaviest draft horse on record is a massive creature.

[Chronos]

And yet, the game has things like Levitate and Telekinesis and immovable rods that depend on knowing monster weights.

[PhoenixPhyre]

And yet, the game has things like Levitate and Telekinesis and immovable rods that depend on knowing monster weights.

Easy solution: levitate handles medium or smaller creatures. Telekinesis handles large and "light weight" (ie things that are spindly or not solidly built) huge creatures. I don't remember what the weight limit is for immovable rod (5k lbs?).

[Greywander]

I'm not, as it would be a massive amount of work with little payoff.
You might have misread the subject of the thread. Obviously giving each individual monster a weight, or range of weights, would be a lot of work (though arguably something they still should have done as part of the stat block), but that's not what's being discussed:

So... is there a formula that can determine a monster's (or animal's) weight using it's size category and strength and maybe basic form (4 legged; animal)?
We're talking about extracting a creature's weight from their size, e.g. if a creature is medium then you know it weighs, say, 80-1000 lbs., with an average weight of 250 lbs. or so. With a chart like that, it would make it a lot easier for a DM to determine a creature's weight on the fly for the times it does matter.

Also, this is something that they've done in previous editions (https://dungeons.fandom.com/wiki/SRD:Table_of_Creature_Size_and_Scale), there's no reason it shouldn't exist for this edition, as well. In fact, it probably wouldn't be much/any different.

It might be interesting to also figure in things like STR, DEX, or CON scores to help narrow down a creature's weight within its size category range. That said, those stats can be expressed in a lot of ways: high CON might mean being slender and fit, or it could mean being robust and girthy. There's a world of difference in the physique of a runner versus a weight lifter, but both are expressed via STR.