A hand (or handbreadth) is a unit of length measurement, usually based on the breadth of a male human hand and thus around 1 dm, i.e. 10 cm.

Today it is only used for the height of horses in the United States and the United Kingdom. In this context, one hand equals four inches (10.16 cm). The horse is measured from the ground to the top of the withers. So a horse that is 15 hands high (abbreviated 15 hh) is 60 inches from the ground to the top of the withers. There are also smaller increments used between the hands. A horse 61 inches tall would be 15.1 hh (said "fifteen one hands high") a horse 62" would be 15.2 hh, 63" would be 15.3 hh, 64" would be 16 hands high.

See also: hand.