International Ring Size Conversion Chart

Ring size
Inside Diameter
Inside Circumference
Sizes
MM Inches MM Inches British & Australian US & Canada French & Russian German Japanese Swiss
14.05 0.553 44.14 1.74 F 3 44 14 4 4
14.15 0.557 44.45 1.75 F 1/2 3.125 - - - -
14.25 0.561 44.77 1.76 F 3/4 3.25 - - - -
14.36 0.565 45.11 1.77 G 3.375 45.25 - 5 5.25
14.45 0.569 54.4 1.79 G 1/4 3.5 - 14.5 - -
14.56 0.573 45.74 1.8 G 1/2 3.625 - - 6 -
14.65 0.577 46.02 1.1 H 3.75 46.5 - - 6.5
14.86 0.585 46.68 1.84 H 1/2 4 - 15 7 -
15.04 0.592 47.25 1.86 I 4.25 47.75 - - 7.75
15.27 0.601 47.97 1.89 I 1/2 4.5 - 15.25 8 -
15.4 0.606 48.38 1.9 J 4.625 49 15.5 - 9
15.53 0.6111 48.79 1.92 J 1/4 4.75 - - - -
15.7 0.618 49.32 1.94 J 1/2 5 - 15.75 9 -
15.8 0.622 49.64 1.95 K 5.1255 50 - - 10
15.9 0.626 49.95 1.97 K 1/4 5.25 - - - -
16 0.63 50.27 1.98 K 1/2 5.375 - - 10 -
16.1 0.634 50.58 1.99 L 5.5 51.75 16 - 11.75
16.3 0.642 51.21 2.02 L 1/4 5.75 - - - -
16.41 0.646 51.55 2.03 L 1/2 5.875 - - - -
16.51 0.65 51.87 2.04 M 6 52.75 16.5 12 12.75
16.71 0.658 52.5 2.07 M 1/2 6.25 - - - -
16.92 0.666 53.16 2.09 N 6.5 54 17 13 14
17.13 0.674 53.82 2.12 N 1/2 6.75 - - - -
17.35 0.683 54.51 2.15 O 7 55.25 17.25 14 15.25
17.45 0.687 54.82 2.16 O 1/2 7.25 - - - -
17.75 0.699 55.76 2.2 P 7.5 56.5 17.75 15 16.5
17.97 0.707 56.45 2.22 P 1/2 7.75 - - - -
18.19 0.716 57.15 2.25 Q 8 57.75 18 16 17.75
18.35 0.722 57.65 2.27 Q 1/2 8.25 - - - -
18.53 0.729 58.21 2.29 Q 3/4 8.5 - 18.5 17 -
18.61 0.733 58.47 2.3 R 8.625 59 - - 19
18.69 0.736 58.72 2.31 R 1/4 8.75 - - - -
18.8 0.74 59.06 2.32 R 1/2 8.875 - - - -
18.89 0.748 59.34 2.35 R 3/4 9 - 19 18 -
19.1 0.752 60 2.36 S 9.125 60.25 - - 20.25
19.22 0.757 60.38 2.38 S 1/4 9.25 - - - -
19.31 0.76 60.66 2.39 S 1/2 9.375 - - - -
19.41 0.764 60.98 2.4 S 3/4 9.5 - 19.5 19 -
19.51 0.768 61.29 2.41 T 9.625 61.5 - - 21.5
19.62 0.772 61.64 2.43 T 1/4 9.75 - - - -
19.84 0.781 62.33 2.45 T 1/2 10 - 20 20 -
20.02 0.788 62.89 2.48 U 10.25 62.75 - 21 22.75
20.2 0.797 63.46 25 U 1/2 10.5 - 20.25 22 -
20.32 .8 63.84 2.51 V 10.625 63 - - 23.75
20.44 0.805 64.21 2.53 V 1/4 10.75 - - - -
20.68 0.814 64.97 2.56 V 1/2 11 - 20.75 23 -
20.76 0.817 65.22 2.57 W 11.125 65 - - 25
20.85 0.821 65.5 2.58 W 1/4 11.25 - - - -
20.94 0.824 65.78 2.59 W 1/2 11.375 - - - -
21.08 0.83 66.22 2.61 W 3/4 11.5 - 21 24 -
21.18 0.834 66.54 2.62 X 11.625 66.25 - - 26.25
21.24 0.836 66.73 2.63 X 1/4 11.75 - - - -
21.3 0.839 66.92 2.64 X 1/2 11.875 - - - -
21.49 0.846 67.51 2.66 Y12 12 67.5 21.25 25 27.5
21.69 0.854 68.14 2.68 Y 1/2 12.25 - - - -
21.89 0.862 68.77 2.71 Z 12.5 68.75 21.75 26 28.75
22.1 0.87 69.43 2.73 Z+1/2 12.75 - - - -
22.33 0.879 70.15 2.76 Z+1 13 - 22 27 -
22.6 0.89 71 2.8 Z+1.5 13.5 - - - -
22.69 0.893 71.28 2.81 Z+2 - - - - -
22.92 0.902 72 2.83 Z+2.5 - - - - -
23.06 0.908 72.45 2.85 Z+3 - - - - -
23.24 0.915 73.01 2.87 Z+3.5 - - - - -
23.47 0.924 73.73 2.9 Z+4 - - - - -
23.55 0.927 73.98 2.91 Z+4.5 - - - - -
23.87 0.94 74.99 2.95 Z+5 - - - - -
24.27 0.956 76.25 3 Z+6 - - - - -
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