A horse’s height is measured in hands. The origin of measuring a horse this way is very old but easy to understand. In days long ago, people did not have the common measuring devices (like tape measures, etc) that we have today.

To measure a horse they used what was handy — their hands! At various times in history and in different locales, a “hand” was defined as the width of a person’s hand using the fingers only, the width of a person’s hand using the fingers and the thumb, the height of a clenched fist, and possibly others. Somewhere along the way the measuring unit of a hand was standardised to mean four inches. Though the origins are ancient, a hand is still the unit of measurement for horses that modern horse owners use today.

The hand is a non-International System (SI) unit of measurement of length standardised to 4 inches (101.6 mm). It is used to measure the height of horses in most horse racing jurisdictions.

The adoption of the international inch in 1959 allowed for a standardised imperial form and a metric conversion. It may be abbreviated to “h” or “hh”.

A horse is measured from the ground to the top of the highest non-variable point of the skeleton, the withers.