Ring size conversions

Inside diameter Inside circumference Sizes
in mm in mm USA & Canada UK, Ireland, Australia, NZ
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
0.498 12.65 1.56 39.7
0.506 12.85 1.59 40.4 C
0.514 13.06 1.61 41
0.522 13.26 1.64 41.7 2 D
0.53 13.46 1.67 42.3
0.538 13.67 1.69 42.9 E
0.546 13.87 1.72 43.6
0.554 14.07 1.74 44.2 3 F
0.562 14.27 1.77 44.8
0.57 14.48 1.79 45.5 G
0.578 14.68 1.82 46.1
0.586 14.88 1.84 46.8 4 H
0.594 15.09 1.87 47.4
0.602 15.29 1.89 48 I
0.61 15.49 1.92 48.7 J
0.618 15.7 1.94 49.3 5
0.626 15.9 1.97 50 K
0.634 16.1 1.99 50.6
0.642 16.31 2.02 51.2 L
0.65 16.51 2.04 51.9 6
0.658 16.71 2.07 52.5 M
0.666 16.92 2.09 53.1
0.674 17.12 2.12 53.8 N
0.682 17.32 2.14 54.4 7
0.69 17.53 2.17 55.1 O
0.698 17.73 2.19 55.7
0.706 17.93 2.22 56.3 P
0.714 18.14 2.24 57 8
0.722 18.34 2.27 57.6 Q
0.73 18.54 2.29 58.3
0.738 18.75 2.32 58.9 R
0.746 18.95 2.34 59.5 9
0.754 19.15 2.37 60.2 S
0.762 19.35 2.39 60.8
0.77 19.56 2.42 61.4 T
0.778 19.76 2.44 62.1 10
0.786 19.96 2.47 62.7 10¼ U
0.794 20.17 2.49 63.4 10½
0.802 20.37 2.52 64 10¾ V
0.81 20.57 2.54 64.6 11
0.818 20.78 2.57 65.3 11¼ W
0.826 20.98 2.59 65.9 11½
0.834 21.18 2.62 66.6 11¾ X
0.842 21.39 2.65 67.2 12
0.85 21.59 2.67 67.8 12¼ Y
0.858 21.79 2.7 68.5 12½ Z
0.866 22 2.72 69.1 12¾
0.874 22.2 2.75 69.7 13
0.882 22.4 2.77 70.4 13¼ Z1
0.89 22.61 2.8 71 13½
0.898 22.81 2.82 71.7 13¾ Z2
0.906 23.01 2.85 72.3 14 Z3
0.914 23.22 2.87 72.9 14¼
0.922 23.42 2.9 73.6 14½ Z4
0.93 23.62 2.92 74.2 14¾
0.938 23.83 2.95 74.8 15
0.946 24.03 2.97 75.5 15¼
0.954 24.23 3 76.1 15½
0.962 24.43 3.02 76.8 15¾
0.97 24.64 3.05 77.4 16