An improperly fitting saddle can be very uncomfortable to ride in. It can also negatively affect your riding position because it is difficult to sit properly in a seat that is too small or too large for you. Once you know your ideal saddle seat size, it is fairly easy to find a saddle that will fit you properly, regardless of your preferences in saddle type and style. English, Western and Australian saddle seats are measured in inches, though they are sized differently due to the shape of the seats.

The most effective way to figure out what size saddle you need is to try sitting and riding in an assortment of different size saddles before you buy one. With any saddle, you should be able to sit in the proper position for your riding discipline and have several finger-widths between the cantle and your backside. You should also have several inches between the front of your body and the pommel. Your legs should rest smoothly and comfortably against the leather without being put at awkward angles or pushed off of the leather part of the saddle. Tall riders often need a slightly larger seat to accommodate for the length of their thigh and leg.

Western Saddles

Western saddles are measured from the backside of the pommel to the front of the cantle in a straight line. On average, your western saddle size will measure two inches smaller than your English saddle size, meaning that a rider who needs a 17 inch English saddle will ride in a 15 inch western saddle. Basic western saddle sizes range from a 15 inch seat to a 19 inch seat with smaller and larger sizes available in some models. A small to medium size adult will ride in a 15 inch saddle, a medium size adult will normally ride in a 16 inch saddle, a large adult will need a 17 inch and an extra large adult will require an 18 inch saddle or larger. Half sizes do exist but are not commonly produced or widely available from most manufacturers.

English Saddles

The seat of an English saddle is measured by stretching a measuring tape or ruler diagonally across the seat from the side screw on the front of the pommel to the middle of the back of the cantle. Common adult seat sizes are 16 inches, 16.5 inches, 17 inches, 17.5 inches and 18 inches, though some saddles are available in both smaller and larger sizes.

As a general rule of thumb, a small adult will ride in a 16 to 16.5 inch saddle. A medium adult will normally need a 16.5 to 17.5 inch saddle and a large adult will need an 18 inch saddle or larger.

The length of the flap on the saddle and the depth of the seat will affect the rider's level of comfort and security even within the specific size range they need.

Australian Saddles

Australian saddles are measured in a straight line between the front of the saddle and the cantle. Due to their design, riders typically need the same size Australian saddle as they do English saddle. Australian saddles are commonly sold in sizes that range between 15 inches and 20 inches. Like western saddles, it is fairly unusual to find an Australian saddle that is sold in half-sizes.