The Bransom Blog

International Ring Sizes

International Ring Size Conversion Chart

Data courtesy of International Ring Sizes

Inside Diameter Inside Circumference Sizes
MM Inches MM Inches British & Australian US & Canada French & Russian German Japanese Swiss
9.91 0.390 31.13 1.22 – 0000 – – – –
10.72 0.442 33.68 1.39 – 00 – – – –
11.53 0.454 36.22 1.43 – 0 – – – –
11.95 0.474 37.54 1.49 A ½ – – – –
12.18 0.482 38.26 1.51 A½ ¾ – – – –
12.37 0.487 38.86 1.53 B 1 – – 1 –
12.60 0.496 39.58 1.56 B½ 1¼ – – – –
12.78 0.503 40.15 1.58 C 1½ – – – –
13.00 0.512 40.84 1.61 C½ 1¾ – – – –
13.21 0.520 41.50 1.63 D 2 41½ 13½ 2 1½
13.41 0.528 42.13 1.66 D½ 2¼ – – – –
13.61 0.536 42.76 1.68 E 2½ 42¾ 13¾ 3 2¾
13.83 0.544 43.45 1.71 E½ 2¾ – – – –
14.05 0.553 44.14 1.74 F 3 44 14 4 4
14.15 0.557 44.45 1.75 F½ 3⅛ – – – –
14.25 0.561 44.77 1.76 F¾ 3¼ – – – –
14.36 0.565 45.11 1.77 G 3⅜ 45¼ – 5 5¼
14.45 0.569 45.40 1.79 G¼ 3½ – 14½ – –
14.56 0.573 45.74 1.80 G½ 3⅝ – – 6 –
14.65 0.577 46.02 1.81 H 3¾ 46½ – – 6½
14.86 0.585 46.68 1.84 H½ 4 – 15 7 –
15.04 0.592 47.25 1.86 I 4¼ 47¾ – – 7¾
15.27 0.601 47.97 1.89 I½ 4½ – 15¼ 8 –
15.40 0.606 48.38 1.90 J 4⅝ 49 15½ – 9
15.53 0.611 48.79 1.92 J¼ 4¾ – – – –
15.70 0.618 49.32 1.94 J½ 5 – 15¾ 9 –
15.80 0.622 49.64 1.95 K 5⅛ 50 – – 10
15.90 0.626 49.95 1.97 K¼ 5¼ – – – –
16.00 0.630 50.27 1.98 K½ 5⅜ – – 10 –
16.10 0.634 50.58 1.99 L 5½ 51¾ 16 – 11¾
16.30 0.642 51.21 2.02 L¼ 5¾ – – – –
16.41 0.646 51.55 2.03 L½ 5⅞ – – – –
16.51 0.650 51.87 2.04 M 6 52¾ 16½ 12 12¾
16.71 0.658 52.50 2.07 M½ 6¼ – – – –
16.92 0.666 53.16 2.09 N 6½ 54 17 13 14
17.13 0.674 53.82 2.12 N½ 6¾ – – – –
17.35 0.683 54.51 2.15 O 7 55¼ 17¼ 14 15¼
17.45 0.687 54.82 2.16 O½ 7¼ – – – –
17.75 0.699 55.76 2.20 P 7½ 56½ 17¾ 15 16½
17.97 0.707 56.45 2.22 P½ 7¾ – – – –
18.19 0.716 57.15 2.25 Q 8 57¾ 18 16 17¾
18.35 0.722 57.65 2.27 Q½ 8¼ – – – –
18.53 0.729 58.21 2.29 Q¾ 8½ – 18½ 17 –
18.61 0.733 58.47 2.30 R 8⅝ 59 – – 19
18.69 0.736 58.72 2.31 R¼ 8¾ – – – –
18.80 0.740 59.06 2.32 R½ 8⅞ – – – –
18.89 0.748 59.34 2.35 R¾ 9 – 19 18 –
19.10 0.752 60.00 2.36 S 9⅛ 60¼ – – 20¼
19.22 0.757 60.38 2.38 S¼ 9¼ – – – –
19.31 0.760 60.66 2.39 S½ 9⅜ – – – –
19.41 0.764 60.98 2.40 S¾ 9½ – 19½ 19 –
19.51 0.768 61.29 2.41 T 9⅝ 61½ – – 21½
19.62 0.772 61.64 2.43 T¼ 9¾ – – – –
19.84 0.781 62.33 2.45 T½ 10 – 20 20 –
20.02 0.788 62.89 2.48 U 10¼ 62¾ – 21 22¾
20.20 0.797 63.46 2.50 U½ 10½ – 20¼ 22 –
20.32 0.800 63.84 2.51 V 10⅝ 63 – – 23¾
20.44 0.805 64.21 2.53 V¼ 10¾ – – – –
20.68 0.814 64.97 2.56 V½ 11 – 20¾ 23 –
20.76 0.817 65.22 2.57 W 11⅛ 65 – – 25
20.85 0.821 65.50 2.58 W¼ 11¼ – – – –
20.94 0.824 65.78 2.59 W½ 11⅜ – – – –
21.08 0.830 66.22 2.61 W¾ 11½ – 21 24 –
21.18 0.834 66.54 2.62 X 11⅝ 66¼ – – 26¼
21.24 0.836 66.73 2.63 X¼ 11¾ – – – –
21.30 0.839 66.92 2.64 X½ 11⅞ – – – –
21.49 0.846 67.51 2.66 Y 12 67½ 21¼ 25 27½
21.69 0.854 68.14 2.68 Y½ 12¼ – – – –
21.89 0.862 68.77 2.71 Z 12½ 68¾ 21¾ 26 28¾
22.10 0.870 69.43 2.73 Z+0.5 12¾ – – – –
22.33 0.879 70.15 2.76 Z+1 13 – 22 27 –
22.60 0.890 71.00 2.80 Z+1.5 13½ – – – –
22.69 0.893 71.28 2.81 Z+2 – – – – –
22.92 0.902 72.00 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 2.90 Z+4 – – – – –
23.55 0.927 73.98 2.91 Z+4.5 – – – – –
23.87 0.940 74.99 2.95 Z+5 – – – – –
24.27 0.956 76.25 3.00 Z+6 – – – – –


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