Hand (unit) divided by four, then the remainder is added after the radix point. Thus, a horse that measures 60 inches is 15 hands high (15 x 4 = 60) and a horse halfway between 15 and 16 hands is 15.2 hands, or 62 inches tall (15 x 4 + 2 = 62) Because the subdivision of a hand is a base 4 system, a horse 64 inches high is 16.0 hands high, not 15.4. A designation of "15.5 hands" is not halfway between 15 and 16 hands, but rather reads 15 hands and five inches, an impossibility in a base 4
Hand (unit) to measure the height of horses, ponies, and other equines. It is used in the U.S., and also in some other nations that use the metric system, such as Canada, Ireland and the UK. In other parts of the world, including continental Europe, and in FEI-regulated international competition, horses are measured in metric units, usually metres or centimetres. In South Africa, measurements may be given in both hands and centimetres, while in Australia, the equestrian regulations stipulate that both measurements are to be given. In those countries where hands are the usual unit for measuring horse height, inches rather than