Fitting an English saddle girth is an easy task that is worth the effort as it saves the trouble of arriving at a stable to ride and discovering that the girth is too short or long. Without a properly fitted girth, the saddle will not be stable, and since saddle stability affects rider stability, a secure saddle is crucial to safety. Save time and trouble by measuring and fitting the girth properly in the beginning, rather than in desperation later.
Gather all equipment and place it near the tie area. Bring the horse around and tie him. Make sure the area is flat and the horse is standing squarely.
If you are using a saddle and pads, place these on the horse just behind the dip of the shoulder bone and withers--where the saddle would go if you were riding.
If you are not using a saddle, skip to the next step.
Take the measuring tape and place one end on the third hole from the bottom of the front billet strap (the straps that the girth attaches to, underneath the main flap) on the left side of the saddle.
If not using a saddle, place the measuring tape approximately half way down the horse's rib cage along the indentation behind the shoulder and withers. If the saddle you will be using is small, such as for a child or small woman, place the tape several inches higher.
Holding the tape in place, pull it gently straight and mark at what point it reaches the horse's left front fetlock joint (ankle). This measurement, rounded to the nearest inch, is how long the girth should be. If no girths come in the size measured, round up to the nearest size.
Different saddles use different girths. If measuring with a dressage saddle in mind, subtract several inches. If using a jumping saddle or smaller saddle, consider adding several inches. Take the width of your horse into account while measuring. A narrow horse such as an Arabian will take a smaller girth than a very fat large pony. Measuring with a saddle is much more accurate than measuring without one. If you have a saddle but are still confused, just run the measuring tape from the third billet hole on one side to the same one on the other side, pull it snug, and use that measurement.
Horses are unpredictable at times, so be sure that your horse is comfortable with you putting things on his back and dangling strings around his legs. Wear proper footwear to avoid squashed toes in case the horse move while you are measuring.