Ring Sizes

Inside Diameter Inside Circumference Sizes
MM Inches MM Inches British & Australian US& Canada
14.05 0.553 44.14 1.74 F 3
14.15 0.557 44.45 1.75 F.5 3.25
14.36 0.565 45.11 1.77 G 3.375
14.56 0.573 45.74 1.80 G.5 3.625
14.65 0.577 46.02 1.81 H 3.75
14.86 0.585 46.68 1.84 H.5 4
15.04 0.592 47.25 1.86 I 4.25
15.27 0.601 47.97 1.89 1.5 4.5
15.40 0.606 48.38 1.90 J 4 .625
15.70 0.618 49.32 1.94 J .5 5
15.80 0.622 49.64 1.95 K 5.25
16.00 0.630 50.27 1.98 K.5 5.375
16.10 0.634 50.58 1.99 L 5.5
16.41 0.646 51.55 2.03 L.5 5.875
16.51 0.650 51.87 2.04 M 6
16.71 0.658 52.50 2.07 M.5 6.25
16.92 0.666 53.16 2.09 N 6.5
17.13 0.674 53.82 2.12 N.5 6.75
17.35 0.683 54.51 2.15 0 7
17.45 0.687 54.82 2.16 0.5 7.25
17.75 0.699 55.76 2.20 P 7.5
17.97 0.707 56.45 2.22 P.5 7 .75
18.19 0.716 57.15 2.25 Q 8
18.35 0.722 57.65 2.27 Q.5 8.25
18.61 0.733 58.47 2.30 R 8.625
18.80 0.740 59.06 2.32 R.5 8.875
19.10 0.752 60.00 2.36 S 9.25
19.31 0.760 60.66 2.39 S.5 9.375
19.51 0.768 61.29 2.41 T 9.625
19.84 0.781 62.33 2.45 T.5 10
20.02 0.788 62.89 2.48 U 10.25
20.20 0.797 63.46 2.50 U.5 10.5
20.32 0.800 63.84 2.51 V 10.625
20.68 0.814 64.97 2.56 V.5 11
20.76 0.817 65.22 2.57 W 11.25
20.94 0.824 65.78 2.59 W.5 11.375
21.18 0.834 66.54 2.62 X 11.625
21.30 0.839 66.92 2.64 X.5 11.875
21.49 0.846 67.51 2.66 Y 12
21.69 0.854 68.14 2.68 Y.5 12.25
21.89 0.862 68.77 2.71 Z 12.5
22.10 0.870 69.43 2.73 Z+.5 12.75