SIZE CM
XS 17.3 - 18.0
S 18.0 - 18.7
M 18.7 - 19.4
L 19.4 - 20.1
XL 20.1 - 20.6

Measure from the base of your palm (the first bend line in wrist) to the tip of your middle finger. These are a guide only, consider girth of hand & tight or loose fit preference too.