How to find the right bits size for your horse?

Choosing the Right Bit Size for Your Horse

At Horse and Balance, we frequently receive inquiries regarding how to determine the correct bit size for a horse. Selecting the appropriate size is essential for both the comfort and performance of your horse. A bit that is too small can cause pinching and irritation at the corners of the lips, while a bit that is too large may shift unsteadily within the mouth. A poorly fitted bit—whether too small or too large—can also result in bruising or even wounds in the horse's mouth. The ideal bit should rest comfortably at the corners of the horse’s mouth, with the mouthpiece extending slightly on each side. The accompanying image illustrates the difference between the cheek piece and mouthpiece for better clarity.

How to Measure Your Current Bit Size

If you already own a TRUST bit but have forgotten its size, you can easily locate the size engraved on the bit, as demonstrated in the photos below. This ensures that you can always quickly reference the size of your bit.

If you don’t yet have a TRUST bit, you can measure your existing bit yourself. To do so, measure the width between the insides of the two rings (cheek piece). For a straight-bar bit, measure from one inner side of the shank to the other.

TRUST offers the following size options: 11.5, 12.5, 13.5, and 14.5. Bradoon bits are available in additional sizes, including half sizes such as 11.5, 12, 12.5, and so on.

Size Chart:
- Size 1 = 11.5
- Size 2 = 12.5
- Size 3 = 13.5
- Size 4 = 14.5

How to Measure for a New Bit

If you have a new horse and are unsure of the correct bit size, you can measure this yourself. A practical method is to use bits of varying sizes that you already have available (the type of bit is not important, as long as you know the size). Place the bit in the horse’s mouth and ensure that the cheek pieces are positioned correctly at the corners of the mouth. Test different sizes to determine the best fit.

If you do not have spare bits to use, another method is to take a 15cm piece of garden hose (or a similarly soft material) and ensure there are no sharp edges. Place the hose in the horse’s mouth as if it were a bit, then mark the spots where it meets the corners of the mouth. While this method is less precise than using an actual bit, it can provide a useful approximation.