Wikia

This table is gratefully copied from d20srd.org.

Table: Creature Size and Scale
Size Category	Attack and AC Modifier	Special Attacks Modifier¹	Hide Modifier	Height or Length²	Weight³	Space⁴	Natural Reach⁴
Size Category	Attack and AC Modifier	Special Attacks Modifier¹	Hide Modifier	Height or Length²	Weight³	Space⁴	Tall	Long
Fine	+8	−16	+16	6 in. or less	1/8 lb. or less	1/2 ft.	0 ft.	0 ft.
Diminutive	+4	−12	+12	6 in.–1 ft.	1/8 lb.–1 lb.	1 ft.	0 ft.	0 ft.
Tiny	+2	−8	+8	1 ft.–2 ft.	1 lb.–8 lb.	2-1/2 ft.	0 ft.	0 ft.
Small	+1	−4	+4	2 ft.–4 ft.	8 lb.–60 lb.	5 ft.	5 ft.	5 ft.
Medium	+0	+0	+0	4 ft.–8 ft.	60 lb.–500 lb.	5 ft.	5 ft.	5 ft.
Large	−1	+4	−4	8 ft.–16 ft.	500 lb.–2 tons	10 ft.	10 ft.	5 ft.
Huge	−2	+8	−8	16 ft.–32 ft.	2 tons–16 tons	15 ft.	15 ft.	10 ft.
Gargantuan	−4	+12	−12	32 ft.–64 ft.	16 tons–125 tons	20 ft.	20 ft.	15 ft.
Colossal and Colossal+	−8	+16	−16	64 ft. or more	125 tons or more	30 ft.	30 ft.	20 ft.
This modifier applies to the bull rush, grapple, overrun, and trip special attacks. Biped's height, quadruped's body length (nose to base of tail) Assumes that the creature is roughly as dense as a regular animal. A creature made of stone will weigh considerably more. A gaseous creature will weigh much less. These values are typical for creatures of the indicated size. Some exceptions exist.

Table: Creature Size and Scale (3.5e Other)