Inner Circumference Ring Sizes Ring Diameter
Inch mm cm U.S.A. U.K. & Australia Inch mm
1.85 47 4.7 4 H 0.586 14.88
1.89 48 4.8 4 1/2 I 0.602 15.29
1.93 49 4.9 5 J 0.619 15.72
1.97 50 5.0 5 1/2 K 0.635 16.13
2.05 52 5.2 6 L 0.652 16.56
2.09 53 5.3 6 1/2 M 0.668 16.97
2.13 54 5.4 7 N 0.685 17.40
2.17 55 5.5 7 1/2 O 0.701 17.80
2.24 57 5.7 8 P 0.717 18.21
2.28 58 5.8 8 1/2 Q 0.734 18.64
2.36 60 6.0 9 R 0.750 19.05
2.40 61 6.1 9 1/2 S 0.767 19.48
2.44 62 6.2 10 T 0.783 19.89
2.48 63 6.3 10 1/2 U 0.800 20.32
2.52 64 6.4 11 V 0.816 20.73
2.56 65 6.5 11 1/2 W 0.833 21.16
2.64 67 6.7 12 X 0.849 21.57
2.68 68 6.8 12 1/2 Y 0.866 22.00
2.71 69 6.9 13 Z 0.882 22.40