creature size and space

Each creature falls into one of six size categories. A creature’s size determines its space and affects its reach.

SizeSpaceReach
Tiny1/2 × 1/20
Small1 × 11
Medium1 × 11
Large2 × 21 or 2
Huge3 × 32 or 3
Gargantuan4 × 4 or larger3 or 4

Published in Rules Compendium, page(s) 199.