The easiest way to determine your handlebar size is to see if it's printed on the handlebar. This will require removing your current stem faceplate.

If you can't find the printed size, there are a couple ways you can measure your handlebar:

Best method: Use a pair of calipers to directly measure the diameter or take your bike to the local bike shop and they will be able to measure it for you.

Alternate method: Use a fabric or paper measuring tape (or print one at ) and measure the circumference of the handlebar right next to your existing stem

- 31.8 mm handlebar will be 99.9 mm in circumference at the center.
- 26.0 mm handlebar will be 81.7 mm in circumference at the center.
- 25.4 mm handlebar will be 79.8 mm in circumference at the center.

Keep in mind that 25.4 and 26.0 mm are very close in size.

If you are not able to measure your handlebar, and you know the make, model, and year of your bike, you may be able to find the handlebar size online at your frame manufacturer's website.