Saddle Gullet Width Calculator

Proper saddle fit starts with the gullet — the channel running along the underside of the saddle that straddles the horse’s spine. The gullet width must match the horse’s wither width to distribute the rider’s weight evenly across the back muscles without pressing on the spine or pinching the shoulders.

Measuring the Wither

To determine gullet width, take a wither tracing using a flexible wire or specialized tool placed 2–3 finger widths behind the shoulder blade (scapula). Press the wire snugly over the withers and down both sides about 20 cm. Transfer this shape to paper and measure the distance between the two sides at a point 7.5 cm (3 inches) below the top of the withers.

Gullet Width Formula

Recommended Gullet Width = Wither Width at 7.5 cm + Clearance Allowance

The clearance allowance is typically 1–2 cm to ensure the saddle does not pinch.

Standard Gullet Sizes

Worked Example

A horse’s wither tracing measures 30 cm across at the 7.5 cm mark:

Recommended gullet = 30 + 1.5 (average clearance) = 31.5 cm

This falls in the Medium range. A medium-tree saddle with a 31–32 cm gullet plate would be appropriate.

Shoulder Angle Consideration

The angle of the wither tracing is equally important. Steep, A-shaped withers (common in Thoroughbreds) need a narrow, angled tree. Flat, table-top withers (common in Quarter Horses) need a wider, flatter tree. The angle at the 7.5 cm measurement point typically falls between 75° and 110°:

A saddle that matches the gullet width but not the angle will still cause problems — bridging on the back or rocking side to side. Always check both measurements.