Discover your size
1) Take a sartorial meter, if you don't have it you can use a simple string.
2) Measure the circumference of your hand at the knuckles (1) without the thumb. If you're using the string mark it, lay it flat and mesure it.
3) Take note of the cm and find out your size consulting the table below.
What if you're uncertain?
If you're uncertain it's advised to choose the smaller size between the two that might be fine. The leather with the use tends to take shape.