Belt size guide

*I measure my waist at the point where I wear my belt, using a tape measure.
* or I measure a belt that I wear from the end of the buckle to the most used hole (usually the middle hole)

belt size

Correspondence table
The most reliable solution is to measure your waistline. 

Belt size (= my waist size) Pants size
80 cm 36
85 cm 38
90 cm 40
95 cm 42
100 cm 44
105 cm 46
110 cm 48/50
120 cm 52/54