The correct method of measurement for an 'English' saddle is different from the method used for a 'Western' saddle. We find that many US riders often specify their saddle size as smaller than really required. For example, a Western 15" saddle equates to a 17" English saddle.
"If you are not experienced in fitting a saddle always find someone who is as this will save you money on buying the wrong saddle"
The image of the saddle shows from where you should measure your 'English' saddle. Take a straight line from the saddle 'nail' (A) to the centre of the cantle (B)....this will give you the actual tree size of your saddle. Generally most sizes below 17" are for Junior riders or very small adults. 17" and 17.5" saddles are the most popular sizes, with 18" and above being more suited to the larger rider.
The width of a saddle is usually denoted by the letters N (narrow), M (medium), W (wide) and XW (extra-wide). These graduations can also be shown numerically by the numbers 2,3,4,5. Some English saddle tree manufacturers will make trees in MW (medium-wide) and NM (narrow-medium) graduations, whereas other European trees may come in centimetre graduations, which can be confusing as different manufacturers use differing means of measuring tree widths.
For example, Prestige offer width fittings from 28cms to 37cms., Stubben offer width fittings from 27cms. to 32 cms, and Amerigo define their width fittings as +/- half a centimetre either side of Medium. Many of the most expensive French Close-Contact saddles are generally only made in a 'regular' medium tree width, with the possibility of a Narrow or Wide option. In England most saddles are manufactured on a BS6635 English tree, which is normally hand-made using laminated beech wood and steel, and guarantees a high standard of quality and strength. However, Synthetic saddle trees are becoming increasingly popular (Bates, Kieffer, Prestige, Passier are all examples), and these now offer great strength, reliability and total symmetry (See Saddlefitting Notes below).
With most high-quality jumping saddles there is an option of flap sizes to suit riders of differing heights and leg lengths. French saddlemakers usually offer flap sizes denoted by the numbers 1,2 and 3, sometimes with intermediates; whereas English jumping saddles may have simpler regular/short/forward/long options. Most top-quality dressage saddles will also offer short, regular and long flap options.