Rings Size Chart

Size Reference Chart
USA U.K. China Japan Diameter Circumference
mm inch mm inch
5 J 1/2 9 9 15.6 0.61 49 1.93
6 M 12 12 16.4 0.65 52 2.05
7 O 14 14 17.3 0.68 54.5 2.15
8 Q 16 16 18.1 0.71 57 2.24
1/2 1/2 17 17 18.5 0.73 58.3 2.30
9 S 18 18 18.9 0.74 59.5 2.34
1/2 S 1/2 19 19 19.3 0.76 60.8 2.39
10 T 1/2 20 20 19.7 0.78 62 2.44
10 1/4 U 21 21 20 0.79 62.7 2.47
10 1/2 1/2 22 22 20.17 0.79 63.4 2.50
11 V 1/2 23 23 20.6 0.81 64.5 2.54
12 Y 25 25 21.4 0.84 67.5 2.66