Ring size conversion chart

Conversion chart for ring sizes (source: Wikipedia)
Inside diameter Inside circumference Sizes
in mm in mm

US,
CA

UK,
IE,
AU,
NZ

IN,
CN,
JP,
S.Amer

IT,
ES,
NL,
CH
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    
0.49 12.45 1.54 39.1 1 B 1  
0.498 12.65 1.56 39.7    
0.506 12.85 1.59 40.4 C   0.5
0.514 13.06 1.61 41   1
0.522 13.26 1.64 41.7 2 D 2 1.75
0.53 13.46 1.67 42.3   2.25
0.538 13.67 1.69 42.9 E 3 3
0.546 13.87 1.72 43.6   3.5
0.554 14.07 1.74 44.2 3 F 4 4.25
0.562 14.27 1.77 44.8 5 4.75
0.57 14.48 1.79 45.5 G   5.5
0.578 14.68 1.82 46.1 6 6
0.586 14.88 1.84 46.8 4 H 7 6.75
0.594 15.09 1.87 47.4   7.5
0.602 15.29 1.89 48 I 8 8
0.61 15.49 1.92 48.7 J   8.75
0.618 15.7 1.94 49.3 5 9 9.25
0.626 15.9 1.97 50 K   10
0.634 16.1 1.99 50.6 10 10.5
0.642 16.31 2.02 51.2 L   11.25
0.65 16.51 2.04 51.9 6 11 11.75
0.658 16.71 2.07 52.5 M 12 12.5
0.666 16.92 2.09 53.1 13 13.25
0.674 17.12 2.12 53.8 N   13.75
0.682 17.32 2.14 54.4 7 14 14.5
0.69 17.53 2.17 55.1 O   15
0.698 17.73 2.19 55.7 15 15.75
0.706 17.93 2.22 56.3 P   16.25
0.714 18.14 2.24 57 8 16 17
0.722 18.34 2.27 57.6 Q   17.5
0.73 18.54 2.29 58.3 17 18.25
0.738 18.75 2.32 58.9 R   19
0.746 18.95 2.34 59.5 9 18 19.5
0.754 19.15 2.37 60.2 S   20.25
0.762 19.35 2.39 60.8 19 20.75
0.77 19.56 2.42 61.4 T   21.5
0.778 19.76 2.44 62.1 10 20 22
0.786 19.96 2.47 62.7 10¼ U 21 22.75
0.794 20.17 2.49 63.4 10½ 22 23.25
0.802 20.37 2.52 64 10¾ V   24
0.81 20.57 2.54 64.6 11 23 24.75
0.818 20.78 2.57 65.3 11¼ W   25.25
0.826 20.98 2.59 65.9 11½ 24 26
0.834 21.18 2.62 66.6 11¾ X   26.5
0.842 21.39 2.65 67.2 12 25 27.25
0.85 21.59 2.67 67.8 12¼ Y   27.75
0.858 21.79 2.7 68.5 12½ Z 26 28.5
0.866 22 2.72 69.1 12¾   29
0.874 22.2 2.75 69.7 13   27 29.75
0.882 22.4 2.77 70.4 13¼ Z1   30.5
0.89 22.61 2.8 71 13½     31
0.898 22.81 2.82 71.7 13¾ Z2   31.75
0.906 23.01 2.85 72.3 14 Z3   32.25
0.914 23.22 2.87 72.9 14¼     33
0.922 23.42 2.9 73.6 14½ Z4   33.5
0.93 23.62 2.92 74.2 14¾     34.25
0.938 23.83 2.95 74.8 15     34.75
0.946 24.03 2.97 75.5 15¼     35.5
0.954 24.23 3 76.1 15½     36.25
0.962 24.43 3.02 76.8 15¾     36.75
0.97 24.64 3.05 77.4 16     37.5