Mesures de la main artlibre jnl.png|thumb|right|250px|Three archaic hand units of measurment:
1: Hand = 4 inches = 10.16 cm
2: Span = 9 inches = 22.86 cm
3: Palm = 3 inches = 7.62 cm ]]

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., about 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 (exactly 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 (152.4 cm) from the ground to the top of the withers. Instead of decimal or vulgar fractions, three inch-long steps are being used between the hands, so a horse 62 inches (157.48 cm) tall would be 15.2 hh (said “fifteen two hands high”). A Pony is less than 14.2 hh.

For FEI purposes a horse can be measured with shoes on or off. In the United Kingdom much official measurement of horses is overseen by the Joint Measurement Board (JMB). For JMB purposes, the shoes must be removed before measurement.

Horses | Units of length | Imperial units | Customary units in the United States | Human-based units of measure

Palmo | Main (unité) | טפח | Palmo | Хэнд