To measure your horse for a cinch, place your saddle on the horse while he's standing on level ground. Tie a piece of string or baling twine to one rigging ring, loop it under the horse's girth, and bring it up to the other ring. Measure that length and subtract 16 inches (round up to the nearest cinch size) and you'll have a good estimate of his correct cinch size. Or measure the girth you are using from buckle to buckle and use that measurement if its a good fit. We can make any size you need. On The English Billets you should make sure you pull through at least 6 inches of billets on both sides.