Ring Sizing Guide

Inside British Size Diameter mm USA Size Inside Diameter mm European Size Inside Diameter mm Inside Japan Size Diameter mm A 11.97 0.5 11.97 B 12.36 1 12.37 1 13.04 1 13.00 C 12.75 1.5 12.78 2 13.36 2 13.33 D 13.14 2 13.21 3 13.67 3 13.66 E 13.53 2.5 13.61 4 13.99 4 14.00 F 13.92 3 14.05 5 14.31 5 14.33 G 14.31 3.5 14.45 6 14.63 6 14.66 H 14.70 4 14.86 7 14.95 7 15.00 I 15.09 4.5 15.27 8 15.27 8 15.33 J 15.48 5 15.70 9 15.58 9 15.66 K 15.87 5.5 16.10 10 15.90 10 16.00 L 16.26 6 16.51 11 16.22 11 16.33 M 16.65 6.5 16.92 12 16.54 12 16.66 N 17.04 7 17.35 13 16.86 13 17.00 O 17.45 7.5 17.75 14 17.17 14 17.33 P 17.86 8 18.19 15 17.49 15 17.66 Q 18.27 8.5 18.59 16 17.81 16 18.00 R 18.68 9 18.89 17 18.13 17 18.33 S 19.09 9.5 19.41 18 18.45 18 18.66 T 19.50 10 19.84 19 18.76 19 19.00 U 19.91 10.5 20.20 20 19.08 20 19.33 V 20.32 11 20.24 21 19.40 21 19.66 W 20.73 11.5 20.68 22 19.72 22 20.00 X 21.14 12 21.08 23 20.04 23 20.33 Y 21.55 12.5 21.49 24 20.35 24 20.66 Z 21.96 13 21.89 25 20.67 25 21.00 13.5 22.33 26 20.99 26 21.33 27 21.31 27 21.66 28 21.63 29 21.94 30 22.26