Here's how you do it

Measure as in the picture, inside a ring. then you will find what you must have arrived at in the overview below.

Wrist measurement (cm) Size (cm)
14 cm 16
15 cm 16
16 cm 17
17 cm 18
18 cm 19
19 cm 20
20 cm 21
21 cm 23
October 18, 2021 — Aleksander Due-Rasmussen