To measure the length of the girth you need, start with placing the saddle pad and saddle on the horse. Using a tape measure, measure the distance from the middle billet hole on one side of the saddle to the same position on the other side. The tape should be placed about one hand’s width behind the horse’s elbow. This measurement equals the size of the girth. As saddles have different sizes and strap lengths, it may be necessary to measure for a new girth if you change your saddle.
To switch between short (dressage) and long girths, add or subtract about 20 inches (51 cm) respectively.