Size is how much space a creature takes up. It decides what it can hide behind, what can hide behind it, and what it can climb.

There are six ranks. Medium is the baseline โ€” a normal human-sized creature or object.

RankExample
TinyRadroach, bloatfly
SmallDog, mole rat
MediumHuman, โ˜ข Ghoul โ€” the baseline
Large๐Ÿ’ช Super Mutant
HugeDeathclaw
GiantBehemoth โ€” anything larger than Huge

Size and Stance

Your stance lowers your effective Size:

StanceEffective Size
๐Ÿง StandingNormal for your creature
๐Ÿ’บ Crouched1 rank lower
Prone2 ranks lower

What Size is used for

Creature Cover

Cover from a body is decided by relative Size, not absolute โ€” see Creature Cover:

  • Same Size or larger in front โ†’ Full Cover (+4 Evasion)
  • One Size smaller in front โ†’ Half Cover (+2 Evasion)
  • Two or more Sizes smaller โ†’ No Cover

Movement

Climb Over clears an obstacle roughly half your Size.

Not the same as item size

Item Sizes measures how many ๐Ÿ”ณ inventory slots an object occupies. That is a separate system that happens to share the word.