For best results, Hidez USA suggests you measure your horse in inches from the ground to the highest point of the withers. This will give you the height of the horse. Next, measure under the heartgirth (where the cinch lays) and around the horse in a vertical line over the withers, as shown in red. Find your horse's measurements in the chart below to determine the "fit" of the suit your horse needs. Three fits are available: Standard, Mid, and Max.