see sizing

How to Measure Ring
Use a piece of paper or thread to circle around your finger. Measure it with a ruler, then refer to Length on the chart.

Size (US) Length (cm)
3
4,3-4,4
4
4,7-4,8
5
4,9-5
6
5,2-5,3
7
5,4-5,6
8
5,7-5,8
9
5,9-6,1
10
6,2-6,3