Last Updated on January 22, 2023
“Size matters not. Look at me. Judge me by my size do you? Hm? Hmm?” Well, apparently Yoda hasn’t played 5e D&D. Maybe he’s more into an older edition.
Contrary to the words of the wise, green jedi, size can be extremely important in D&D. This one little mechanic can have huge implications in both combat and exploration.
In today’s article, we’re going to be discussing what those options are.
Creature Size in 5e
Creature size in D&D is a fairly simple mechanic. Each creature exists within a size category, from Tiny to Gargantuan, and these sizes determine how much space a creature actually takes up.
Creature Size Categories
Now, aside from a Gelatinous Cube, most creatures aren’t going to fill their space entirely.
Rather, this size measurement represents how much space they occupy in battle. If that sounds confusing, don’t worry, you’re not alone.
Let’s start by talking about a human. Your average human (in real life) is about 5’4”.
If we were to be real rough with our estimates and averages, an adult human in a normal standing position fills the space of a cylinder that’s 5 feet high and 1 foot in diameter.
That is super complicated right? No one wants to sit around figuring out the volume of each creature in D&D – that’s 1000’s of creatures!
No, instead, we talk about rough averages. The cube generalization works for a couple reasons.
First, it’s simple. On a battlemat that uses 5-foot squares, it is very easy to visualize a 5-foot cube.
Second, creatures move around. Especially in combat, the characters on the battlefield aren’t going to be rigidly standing at attention. They’ll likely be standing in a readied position, weapons drawn.
Realistically, they’re also constantly moving around; we just don’t see that in real time since we have to roll a lot of dice.
So, medium creatures take up a 5-foot square. Other creatures occupy their space accordingly, and there are more mechanics that are related to that.
What Does Size Govern in 5e?
Other than the space a creature occupies, there are several things that can be affected by a creature’s size category.
Keep in mind that we’re talking about creatures here, and not all of the things we’re about to cover have any jurisdiction over player characters.
In the “Creating a Monster” section of the DMG found on page 273, one of the steps is naturally assigning a creature its hit points.
To do this, you determine which Hit Dice you’ll be using and how many of them you need to get the appropriate amount of hit points for the CR you’re looking for.
The hit dice are each associated with a different size category, and you’ll notice that most published creatures reflect this in their stat block. Below is the table for hit dice based on size category.
Hit Dice by Size Category
You’ll notice we’ve included average hit points for each die. This is the average roll, which yes, works out to include half a hit point each time.
When creating a monster, their hit points are often determined by their average hit points. Therefore, a medium creature with 4 hit dice would have 18 hit points.
This rule does apply to PCs. The weight a creature can carry, lift, or drag and a creature’s carrying capacity is increased or decreased based on their size.
For each size category larger than Medium, the weight for all of these is doubled. For Tiny creatures, the weight of all these is halved. By this logic, Small and Medium creatures calculate normally.
Normal calculation is as follows:
- Carrying Capacity – Strength score x 15 (lbs.)
- Push, Drag, Lift – Strength score x 30 (lbs.); If you’re working with weight in excess of your carrying capacity, your speed is reduced to 5 feet.
This is a bit of an obscure rule, but it’s part of the DMG’s monster creation chapter, and so we’ll count it.
Since creatures of larger sizes tend to carry oversized weapons (again, Medium is the default) their weapons tend to deal more damage.
The suggestion from the DMG is to increase the amount of damage dice (not the type of dice) for each size category greater than Medium.
Double the damage dice for a Large creature, triple for a Huge, and quadruple for a Gargantuan. Tiny creatures don’t have their damage dice halved, since you can’t easily cut one die in half.
For a greatsword, this might look something like this:
Damage Dice by Size Category (Greatsword)
Grappling and Similar Mechanics
The rule for grappling is that you cannot grapple a creature more than one size larger than you. This applies just as much to creatures as they do to PCs. A Tiny sprite certainly isn’t putting an ancient black dragon in a chokehold.
This sort of common-sense rule applies to a lot of interaction actions. Things like swallowing, engulfing, shoving, any sort of interaction that would just be impossible between two creatures with a large size gap.
For example, the Shambling Mound has an ability titled engulf. This ability, which engulfs a creature grappled by it, can only be used on Medium or smaller creatures.
Since the Shambling Mound is a large creature, it shouldn’t be able to engulf a creature that’s as large as it is or any larger.
This one is anything but a rule. However, often you’ll see larger creatures benefit from an appropriate reach distance for their melee attacks. Because creatures come in various shapes, it’s not as easy to say all gargantuan creatures have a 20-foot reach, etc.
Interestingly, larger creatures do have a larger reach in a way. A Large creature with a melee attack that reaches 5 feet actually has a larger effective radius than a Medium creature with the same melee attack.
This is because of the first thing we talked about, the space a creature occupies. A Large creature takes up 4 squares. That means that its 5-foot attack can hit creatures in the surrounding 12 squares!
Compare that to the Medium creatures effective radius of the surrounding 8 squares, and that’s quite an improvement.
Creatures and PCs have the ability to squeeze through spaces large enough for creatures one size smaller than they are.
While doing so, the creature spends 1 extra foot for every foot it moves through the space. They also have disadvantage on attack rolls and Dexterity saving throws, and attack rolls made against them are made with advantage.
Squeezing isn’t necessarily a common mechanic, but when used skillfully, it can make for some very interesting encounters, both in and out of combat.
Creatures can escape through tunnels, hide inside of holes in a wall, and do all sorts of things that your players won’t be anticipating.
Creature Sizes in Battle
Originally, I was going to break this into two sections. One would talk about the DM’s perspective, and the other would discuss what it’s like for players.
Fortunately for you, creature sizes impact how both sides of the DM screen interact with the battlefield.
With all the mechanics we’ve discussed above, by far the most important is the most simple.
Creatures occupy their space. Because of this, larger creatures have much larger hit boxes. This means a couple things.
For starters, they can be surrounded by the players and take much more frequent damage. Even for spellcasters using large AOE spells, they just have to hit the creature’s space to be able to hit it.
Something like Pulse Wave, which affects a 30-foot cone, doesn’t have to entirely encompass a Gargantuan creature to deal damage to it; it just has to touch it, leaving a lot of open real estate for any minions in the area to catch some damage as well.
The other thing we want to note is that larger creatures can command the battlefield. Their size can be used to block exits or even just stop a character from easily moving to their destination.
Most player characters can’t move through a creature’s space, so they’ll have to go around if they want to end up on the other side.
This sort of battlefield presence works really well if the larger creature isn’t the only opposition to the players.
A tactically minded group of enemies will situate themselves around the larger creature and make movement for the players near impossible without incurring opportunity attacks.
Being Creative With Size
What would a good mechanic article here at Black Citadel be without a bit of homebrew discussion.
Size is a mechanic that is extremely generalized and works very well. There isn’t much that needs to be changed, but we can certainly play around with it to make more interesting combat encounters.
Going off of the basis that creatures all occupy the entirety of their space is helpful for easy, straightforward play. Unfortunately, it eliminates some possibilities that can feel more cinematic.
Let’s start by talking about a Storm Giant, a huge creature. Storm giants are the largest of the giants and rank the highest in the ordning, but that’s not important right now.
What is important is that they are just about as huge as you can get without being gargantuan. That means something very important to us: large legs.
Normally, creatures can’t invade another creature’s personal space, but that seems a bit silly.
How often have we seen heroes dash between the legs of a giant, ogre, or troll to get a more tactical advantage? There comes a point where creatures are not just big, they’re obstacles.
What I’m proposing is that you allow your players to interact with very large creatures in ways that make sense. Nothing crazy, just treating them like a piece of the environment.
This might mean sliding between their legs, climbing up their back, or even trying to topple them over AT-AT style.
You don’t have to be specific about these things, but you can make it clear before playing that very large creatures can be interacted with in creative ways.
Then it’s up to the players to say “I want to cast spider climb on the barbarian and have them walk up the giant’s back to stab it in the throat,” or “I want to jump on top of the dragon and try to confuse it.”
If you thought I was just going to throw the players a freebie, you’re mistaken. Just as common as the “climbing a giant” trope is the “oh no, I’ve made a mistake and am now being thrown/eaten by a giant trope.”
Okay, maybe the trope isn’t that specific, but you see what I’m getting at. Getting up close and personal with a very large creature is dangerous.
You can incorporate this in whichever way you see as fitting. Maybe a blanket rule like “If a character moves within a creature’s space, the creature has advantage on attack rolls against the character and strength checks to grapple them.
You can also be more reactive to the player’s specific creative moments.
Crawling under a dragon might mean the dragon just lays down on them and they take a few d10 bludgeoning damage on a failed Dex save and half as much on a success.
Any solution you come up with should be simple, both for your sake and the players. You don’t want to create three paragraphs of hyper-specific state based rules for situations that just might never happen.
So there you have it. Maybe Yoda would have recognized the importance of size if he was trying to force push a tarrasque away from him.
Fortunately, you can now be much the wiser and use size to its full potential in your next 5e encounter.
As always, happy adventuring.
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As a kid, I was often told to get my head out of the clouds and to stop living in a fantasy world. That never really jived with me, so I decided to make a living out of games, stories, and all sorts of fantastical works. Now, as an adult, I aspire to remind people that sometimes a little bit of fantasy is all you need when life gets to be too much.