Ring sizes

SIZE DIAMETER (MM) USA
5 14.65 3 3/4
7 15.04 4
8 15.20 4 1/2
9 15.40 5
10 15.80 5 1/8
11 16.10 5 3/4
12 16.51 6
13 16.92 6 1/2
14 17.15 6 3/4
15 17.35 7
16 17.75 7 1/2
17 18.19 8
18 18.61 8 1/2