<P> The hand is a non-SI unit of measurement of length standardized to 4 inches (101.6 mm). It is used to measure the height of horses in some English - speaking countries, including Australia, Canada, the Republic of Ireland, the United Kingdom and the United States . It was originally based on the breadth of a human hand . The adoption of the international inch in 1959 allowed for a standardized imperial form and a metric conversion . It may be abbreviated to "h" or "hh". Although measurements between whole hands are usually expressed in what appears to be decimal format, the subdivision of the hand is not decimal but is in base 4, so subdivisions after the radix point are in quarters of a hand, which are inches . Thus, 62 inches is fifteen and a half hands, or 15.2 hh (normally said as "fifteen - two", or occasionally in full as "fifteen hands two inches"). </P> <P> "Hands" may be abbreviated to "h", or "hh". The "hh" form is sometimes interpreted as standing for "hands high ." When spoken aloud, hands are stated by numbers, 15.0 is "fifteen hands", 15.2 is alternately "fifteen - two" or "fifteen hands, two inches," and so on . </P>

How many inches in a hand for measuring horses