Ring Size Conversion

US, UK, Australia, China, Canada, Japan Comparision Chart

Convert ring sizes between american, british, australian, canadian, chinese, japanese and in inches and millimeters (mm) for diameter and circumference.

For your information, circumference of a ring is the measure of the length around the circle. The diameter of a ring is the measure of the distance across the middle inside.

Please note that there is no real international standard for ring sizing. You may need to contact to the manufacturer for exact sizes.

For other types of size conversions, please go back to Size Converter .

Ring Size Table

US/Canada UK/Australia Japan China Diameter (inch) Diameter (mm) Circumference (inch) Circumference (mm)
0 - - - 0.458 11.63 1.44 36.5
¼ - - - 0.466 11.84 1.46 37.2
½ A - - 0.474 12.04 1.49 37.8
¾ - - 0.482 12.24 1.51 38.5
1 B 1 1 0.49 12.45 1.54 39.1
- - 0.498 12.65 1.56 39.7
C - - 0.506 12.85 1.59 40.4
- - 0.514 13.06 1.61 41.0
2 D 2 2 0.522 13.26 1.64 41.7
- - 0.53 13.46 1.67 42.3
E 3 3 0.538 13.67 1.69 42.9
- - 0.546 13.87 1.72 43.6
3 F 4 4 0.554 14.07 1.74 44.2
5 5 0.562 14.27 1.77 44.8
G - - 0.57 14.48 1.79 45.5
6 6 0.578 14.68 1.82 46.1
4 H 7 7 0.586 14.88 1.84 46.8
- - 0.594 15.09 1.87 47.4
I 8 8 0.602 15.29 1.89 48.0
J - - 0.61 15.49 1.92 48.7
5 9 9 0.618 15.70 1.94 49.3
K - - 0.626 15.90 1.97 50.0
10 10 0.634 16.10 1.99 50.6
L - - 0.642 16.31 2.02 51.2
6 11 11 0.65 16.51 2.04 51.9
M 12 12 0.658 16.71 2.07 52.5
13 13 0.666 16.92 2.09 53.1
N - - 0.674 17.12 2.12 53.8
7 14 14 0.682 17.32 2.14 54.4
O - - 0.69 17.53 2.17 55.1
15 15 0.698 17.73 2.19 55.7
P - - 0.706 17.93 2.22 56.3
8 16 16 0.714 18.14 2.24 57.0
Q - - 0.722 18.34 2.27 57.6
17 17 0.73 18.54 2.29 58.3
R - - 0.738 18.75 2.32 58.9
9 18 18 0.746 18.95 2.34 59.5
S - - 0.754 19.15 2.37 60.2
19 19 0.762 19.35 2.39 60.8
T - - 0.77 19.56 2.42 61.4
10 20 20 0.778 19.76 2.44 62.1
10¼ U 21 21 0.786 19.96 2.47 62.7
10½ 22 22 0.794 20.17 2.49 63.4
10¾ V - - 0.802 20.37 2.52 64.0
11 23 23 0.81 20.57 2.54 64.6
11¼ W - - 0.818 20.78 2.57 65.3
11½ 24 24 0.826 20.98 2.59 65.9
11¾ X - - 0.834 21.18 2.62 66.6
12 25 25 0.842 21.39 2.65 67.2
12¼ Y - - 0.85 21.59 2.67 67.8
12½ Z 26 26 0.858 21.79 2.70 68.5
12¾ - - 0.866 22.00 2.72 69.1
13 - 27 27 0.874 22.20 2.75 69.7
13¼ Z1 - - 0.882 22.40 2.77 70.4
13½ - - - 0.89 22.61 2.80 71.0
13¾ Z2 - - 0.898 22.81 2.82 71.7
14 Z3 - - 0.906 23.01 2.85 72.3
14¼ - - - 0.914 23.22 2.87 72.9
14½ Z4 - - 0.922 23.42 2.90 73.6
14¾ - - - 0.93 23.62 2.92 74.2
15 - - - 0.938 23.83 2.95 74.8
15¼ - - - 0.946 24.03 2.97 75.5
15½ - - - 0.954 24.23 3.00 76.1
15¾ - - - 0.962 24.43 3.02 76.8
16 - - - 0.97 24.64 3.05 77.4