Size And Reach

Combat Overview

A creature's size determines how much space it occupies on the battlefield, how far it can naturally reach, and what modifiers it applies to attacks, AC, and combat maneuvers. These numbers come up constantly — every time a Large monster attacks a PC standing two squares away, or a player asks "can my reach weapon hit that?" — so knowing them by feel matters more than memorising them.

Size Categories

Size	Space	Reach (tall)	Reach (long)	Atk / AC	CMB / CMD	Stealth	Fly
Fine	½ ft	0 ft	0 ft	+8	−8	+16	+8
Diminutive	1 ft	0 ft	0 ft	+4	−4	+12	+4
Tiny	2½ ft	0 ft	0 ft	+2	−2	+8	+2
Small	5 ft	5 ft	5 ft	+1	−1	+4	+2
Medium	5 ft	5 ft	5 ft	—	—	—	—
Large	10 ft	10 ft	5 ft	−1	+1	−4	−2
Huge	15 ft	15 ft	10 ft	−2	+2	−8	−4
Gargantuan	20 ft	20 ft	15 ft	−4	+4	−12	−6
Colossal	30 ft	30 ft	20 ft	−8	+8	−16	−8

Medium is the baseline — all modifiers are 0. Fine/Diminutive/Tiny creatures occupy less than a 5-ft square; multiple can share the same square. Their reach is 0 ft, meaning they must enter a target's square to make a melee attack. Tall = bipedal / upright body shape. Long = quadruped / horizontal body shape (horse, serpent, dragon).

Threatened-Square Visualiser

Size category

Long creature

Reach weapon

Creature (body) Threatened (natural reach) Reach weapon extension Dead zone — reach weapon cannot hit here Not threatened

Reach Weapons

A reach weapon lets a wielder strike targets farther away than normal. Most reach weapons double the wielder's natural reach — a Medium fighter with a longspear threatens squares 10 ft away instead of 5 ft.

The dead zone — the most commonly missed rule: reach weapons cannot attack adjacent squares. A Medium fighter with a longspear threatens the 10-ft ring but cannot attack the creature standing right next to them. Step back 5 ft or draw a different weapon to threaten adjacent squares again.

For larger creatures, the dead zone is the ring of squares immediately adjacent to the creature's body (within 5 ft of any edge). Their natural attacks and natural weapons can still reach those squares — only the manufactured reach weapon cannot. Toggle the "Reach weapon" checkbox in the visualiser above to see exactly which squares become the dead zone for any size.

Squeezing

A creature can squeeze through a space one size category smaller than its own (e.g. a Large creature can squeeze through a Medium-width opening). While squeezing:

½ speed

Movement is halved while squeezing

−4 AC

Penalty to Armor Class

−4 attack

Penalty to all attack rolls

Provokes AoO

Entering a squeezed space provokes attacks of opportunity

A creature cannot squeeze through a space two or more size categories smaller. A Huge creature cannot pass through a Small doorway regardless of how long it takes.

Size Modifiers — Full Reference

Size	Attack & AC	CMB & CMD	Grapple	Stealth	Fly	Perception (vs. creatures)
Fine	+8	−8	−16	+16	+8	—
Diminutive	+4	−4	−8	+12	+4	—
Tiny	+2	−2	−4	+8	+2	—
Small	+1	−1	−2	+4	+2	—
Medium	—	—	—	—	—	—
Large	−1	+1	+2	−4	−2	—
Huge	−2	+2	+4	−8	−4	—
Gargantuan	−4	+4	+8	−12	−6	—
Colossal	−8	+8	+16	−16	−8	—

Grapple modifiers are separate from standard CMB — larger creatures have an additional size bonus to grapple checks specifically. Perception has no size modifier in PF1e core; larger creatures are simply easier to spot visually (GM discretion).