Here you can see our size guide for briefs. Measure around the hips.

34 = XXS = 88-91 cm
36 = XS = 92-95 cm
38 = S = 96-99 cm
40 = M = 100-103 cm
42 = L = 104-107 cm
44 = XL = 108-111 cm
46 = XXL= 112-115 cm