1 A hand is equal to 4 inches or 10.2cms. 2  You should measure your horse from the point of the withers to the ground. 3  A horse that is 61 inches tall is 15.1 hands or 15 hands and 1 inch or 15.1hh. 4  This is calculated using (61/4 = 15.25); the .25 is the decimal equivalent of one quarter and a quarter of 4 = 1; so 15.1hh.