Ring Sizing

Conversion chart for ring sizes – Source: Wikipedia
Inside diameter Inside circumference Sizes
(in) (mm) (in) (mm) United States
Canada
Mexico		 United Kingdom, Ireland
Australia, New Zealand		 China, Japan
South America		 India Italy, Spain
Netherlands, Switzerland
0.458 11.63 1.44 36.5 0
0.466 11.84 1.46 37.2 ¼
0.474 12.04 1.49 37.8 ½ A
0.482 12.24 1.51 38.5 ¾ A½
0.49 12.45 1.54 39.1 1 B 1
0.498 12.65 1.56 39.7 1¼ B½
0.506 12.85 1.59 40.4 1½ C 0.5
0.514 13.06 1.61 41 1¾ C½ 1 1
0.522 13.26 1.64 41.7 2 D 2 2 1.75
0.53 13.46 1.67 42.3 2¼ D½ 2.25
0.538 13.67 1.69 42.9 2½ E 3 3 3
0.546 13.87 1.72 43.6 2¾ E½ 4 3.5
0.554 14.07 1.74 44.2 3 F 4 4.25
0.562 14.27 1.77 44.8 3¼ F½ 5 5 4.75
0.57 14.48 1.79 45.5 3½ G 5.5
0.578 14.68 1.82 46.1 3¾ G½ 6 6 6
0.586 14.88 1.84 46.8 4 H 7 6.75
0.594 15.09 1.87 47.4 4¼ H½ 7 7.5
0.602 15.29 1.89 48 4½ I 8 8 8
0.61 15.49 1.92 48.7 4¾ J 9 8.75
0.618 15.7 1.94 49.3 5 J½ 9 9.25
0.626 15.9 1.97 50 5¼ K 10 10
0.634 16.1 1.99 50.6 5½ K½ 10 10.5
0.642 16.31 2.02 51.2 5¾ L 11 11.25
0.65 16.51 2.04 51.9 6 L½ 11 12 11.75
0.658 16.71 2.07 52.5 6¼ M 12 12.5
0.666 16.92 2.09 53.1 6½ M½ 13 13 13.25
0.674 17.12 2.12 53.8 6¾ N 13.75
0.682 17.32 2.14 54.4 7 N½ 14 14 14.5
0.69 17.53 2.17 55.1 7¼ O 15 15
0.698 17.73 2.19 55.7 7½ O½ 15 15.75
0.706 17.93 2.22 56.3 7¾ P 16 16.25
0.714 18.14 2.24 57 8 P½ 16 17 17
0.722 18.34 2.27 57.6 8¼ Q 17.5
0.73 18.54 2.29 58.3 8½ Q½ 17 18 18.25
0.738 18.75 2.32 58.9 8¾ R 19 19
0.746 18.95 2.34 59.5 9 R½ 18 19.5
0.754 19.15 2.37 60.2 9¼ S 20 20.25
0.762 19.35 2.39 60.8 9½ S½ 19 21 20.75
0.77 19.56 2.42 61.4 9¾ T 21.5
0.778 19.76 2.44 62.1 10 T½ 20 22 22
0.786 19.96 2.47 62.7 10¼ U 21 23 22.75
0.794 20.17 2.49 63.4 10½ U½ 22 23.25
0.802 20.37 2.52 64 10¾ V 24 24
0.81 20.57 2.54 64.6 11 V½ 23 25 24.75
0.818 20.78 2.57 65.3 11¼ W 25.25
0.826 20.98 2.59 65.9 11½ W½ 24 26 26
0.834 21.18 2.62 66.6 11¾ X 26.5
0.842 21.39 2.65 67.2 12 X½ 25 27 27.25
0.85 21.59 2.67 67.8 12¼ Y 28 27.75
0.858 21.79 2.7 68.5 12½ Z 26 28.5
0.866 22 2.72 69.1 12¾ Z½ 29 29
0.874 22.2 2.75 69.7 13 27 30 29.75
0.882 22.4 2.77 70.4 13¼ Z1 30.5
0.89 22.61 2.8 71 13½ 31 31
0.898 22.81 2.82 71.7 13¾ Z2 32 31.75
0.906 23.01 2.85 72.3 14 Z3 32.25
0.914 23.22 2.87 72.9 14¼ 33 33
0.922 23.42 2.9 73.6 14½ Z4 33.5
0.93 23.62 2.92 74.2 14¾ 34 34.25
0.938 23.83 2.95 74.8 15 35 34.75
0.946 24.03 2.97 75.5 15¼ 35.5
0.954 24.23 3 76.1 15½ 36 36.25
0.962 24.43 3.02 76.8 15¾ 36.75
0.97 24.64 3.05 77.4 16 37 37.5