Ring Sizes

Size Inside Diameter (mm) Inside Circumference (mm)
1 12.5 39.3
1.5 12.9 40.5
2 13.3 41.8
2 1/2 13.8 43.4
3 14.2 44.6
3 1/2 14.6 45.9
4 15 47.1
4 1/2 15.4 48.4
5 15.8 49.6
5 1/2 16.2 50.9
6 16.6 52.2
6 1/2 17 53.4
7 17.4 54.7
7 1/2 17.9 56.2
8 18.3 57.5
8 1/2 18.7 58.7
9 19.1 60.0
9 1/2 19.5 61.3
10 19.9 62.5
10 1/2 20.3 63.8
11 20.7 65.0
11 1/2 21.1 66.3
12 21.5 67.5
12 1/2 21.9 68.8
13 22.3 70.1