What saddle seat size and flap do I need, especially if I'm tall?

Utah State University Extension's fact sheet on fitting a saddle to the rider says an English seat is measured from the button on either side of the pommel to the middle of the top of the cantle, and that seat sizes run from about 12 to 18 inches across saddle types.

Makers don't all measure the same way. Dr. Joyce Harman, a veterinarian and saddle-fit expert writing for EquiSearch, says that for English saddles one maker's method runs from the center of the cantle to a line across the front of the tree, minus about a quarter inch for the roll of leather there, while a rider's method runs from the cantle to the buttons on the side of the pommel. She also notes that the buttons are often uneven, so you should measure on both sides.

Her advice about the number itself is blunt: it is best to toss out the numbers and see how the saddle fits you. Seat depth matters as much as length, she says, since deeper seats raise the pommel and cantle and you need more length to avoid being pushed against the front.

Seat size also isn't the same thing as tree width or gullet width, which describe how the saddle fits the horse. For that, see our page on how to measure a saddle gullet.

Harman says thigh length often determines seat size, and that there must be room for your buttocks. Sitting in the saddle, she suggests leaving about the same space in front of and behind you, roughly two to four inches for an English saddle. Your knee should reach about the center of the knee roll, depending on the style of saddle, and nothing should poke into your thigh or leave you feeling constricted.

Utah State's check at the back: with you in the saddle, there should be about four fingers' room between your seat and the top of the cantle, and a full hand and thumb is too much, which means the saddle is too big. A saddle that is too big, the fact sheet says, has the rider sitting behind the stirrup and riding behind the horse's motion. A saddle that is too small leaves the rider uncomfortable, without enough room for seat or legs. The sheet also notes the cantle can rub the back of the thigh if it ties in under the leg.

Height is not the same as thigh length, which is why a rider's body can surprise you. One rider told us she was 5 feet tall and weighed 125 pounds, and that a 15 3/4 inch seat was almost perfect for her because she was leggy for her size.

Eventually it comes to a try-on. Sit in the saddle on your own horse, or ask a fitter to put you on a few, and run through the checks above.

Seat size and flap are separate questions: seat size is a length along the seat, while the flap is about where your leg and knee sit.

Jim Wofford, writing in Practical Horseman (syndicated by EquiSearch), says the flap should extend slightly past the knee when you look at it from the side. Dressage flaps are long and drop nearly straight down, while jumping flaps are shorter and angle forward, around 45 degrees on close-contact saddles. The flap's angle has to leave room for your knee at your stirrup length: a nearly vertical flap leaves no room for the knee when your leathers are short.

Utah State's fact sheet gives the same idea from the boot's point of view: the leg flap should extend below the top of your boot in every position, and your knee should sit on the flap without riding over its front edge. If you ride in tall boots or half chaps, check both with them on.

Wofford's test is to shorten your stirrups for each phase of riding and look at where the knee and flap fall. His point is that a saddle can fit the horse correctly and still put the rider in the wrong place.

The sources we read don't give a height-to-size chart, and we won't make one up. Harman says thigh length often determines seat size, so that is the number to know. Wofford and Utah State describe the flap as something that has to suit your leg, boots and stirrup length.

Riders with long legs describe it in their own words. One parent wrote that her 13-year-old daughter is 5 feet 7 inches and needed a saddle with a flap long enough for her long femurs. A blogger said the flaps on one saddle were longer and more forward to suit riders who are long from hip to knee, and that her own femurs are long. These are individual experiences with particular saddles, and they show the problem more than they give a rule.

Read them with one caution. Brands name and build flaps differently, so a 'long' or 'forward' flap on one saddle may not match another. Ask the maker how the flap is cut and what length it is, and ask a fitter which models suit your leg.

Our English saddles and accessories are a place to see the range. This page is about English saddles; western saddles are sized differently, so follow the maker's guide or ask a fitter.

Wofford says your seat bones should rest at the saddle's balance point when your stirrups are the right length for your discipline, and that this point moves with the discipline. In dressage the balance point sits less than a foot behind the pommel, and shorter jumping or cross-country stirrups move your seat back. He adds that dual-purpose saddles can work at the lower levels of eventing, but every extra discipline is a compromise.

That ties seat and flap to your stirrup length, which is worth knowing before you buy. Our page on what length stirrup leathers you need covers the leather side, and the girth that goes with a long-flap or dressage saddle is on long girth or dressage girth.

Harman also says that the number alone won't tell you if a saddle suits you. Seat depth and where the center of the seat falls also change how a 17 feels.

A saddle has to fit the horse first. Horse & Hound asked Ruth Spencer, a master saddle fitter who sits on the board of the Society of Master Saddlers assessors, how often to book. Her answer was at least every six to 12 months, and more often for horses in regular work, young horses, those changing shape in training or coming back after time off.

She says to look for a fitter qualified through the Society, such as a Qualified Saddle Fitter, and that ongoing professional development and insurance are good signs. Horse & Hound says a standard check takes 45 to 90 minutes and includes assessing the horse standing and in motion, templating, evaluating the saddle on and off the horse, and checking flocking and balance.

That is the horse's side. A fitter can also watch you in the saddle, which is why this page ends here: seat size and flap are what to bring to the conversation, not what to settle by yourself. Take your thigh measurement, the stirrup length you ride, your discipline and the saddles you have tried. If you are in the US and can't find a fitter through a society, look for one who is qualified and insured, and ask what training they have had.

If your horse is sore, reluctant to be tacked up, or going differently, call your vet too. A pad, a different gullet or a different saddle won't diagnose anything.