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Ring Size Conversion




Sizes Inside Diameter   Inside Circumference
 US & Canada British & Australian French & Russian German Japanese Swiss MM Inches MM Inches
1/2 A - - - - 11.95 0.474 37.54 1.49
3/4 A 1/2 - - - - 12.18 0.482 38.26 1.51
1 B - - 1 - 12.37 0.487 38.86 1.53
1 1/4 B 1/2 - - - - 12.6 0.496 39.58 1.56
1 1/2 C - - - - 12.78 0.503 40.15 1.58
1 3/4 C 1/2 - - - - 13 0.512 40.84 1.61
2 D 41 1/2 13 1/2 2 1 1/2 13.21 0.52 41.5 1.63
2 1/4 D 1/2 - - - - 13.41 0.528 42.13 1.66
2 1/2 E 42 3/4 13 3/4 3 2 3/4 13.61 0.536 42.76 1.68
2 3/4 E 1/2 - - - - 13.83 0.544 43.45 1.71
3 F 44 14 4 4 14.05 0.553 44.14 1.74
3 1/8 F 1/2 - - - - 14.15 0.557 44.45 1.75
3 1/4 F 3/4 - - - - 14.25 0.561 44.77 1.76
3 3/8 G 45 1/4 - 5 5 1/4 14.36 0.565 45.11 1.77
3 1/2 G 1/4 - 14 1/2 - - 14.45 0.569 45.4 1.79
3 5/8 G 1/2 - - 6 - 14.56 0.573 45.74 1.8
3 3/4 H 46 1/2 - - 6 1/2 14.65 0.577 46.02 1.81
4 H 1/2 - 15 7 - 14.86 0.585 46.68 1.84
4 1/4 I 47 3/4 - - 7 3/4 15.04 0.592 47.25 1.86
4 1/2 I 1/2 - 15 1/4 8 - 15.27 0.601 47.97 1.89
4 5/8 J 49 15 1/2 - 9 15.4 0.606 48.38 1.9
4 3/4 J 1/4 - - - - 15.53 0.611 48.79 1.92
5 J 1/2 - 15 3/4 9 - 15.7 0.618 49.32 1.94
5 1/8 K 50 - - 10 15.8 0.622 49.64 1.95
5 1/4 K 1/4 - - - - 15.9 0.626 49.95 1.97
5 3/8 K 1/2 - - 10 - 16 0.63 50.27 1.98
5 1/2 L 51 3/4 16 - 11 3/4 16.1 0.634 50.58 1.99
5 3/4 L 1/4 - - - - 16.3 0.642 51.21 2.02
5 7/8 L 1/2 - - - - 16.41 0.646 51.55 2.03
6 M 52 3/4 16 1/2 12 12 3/4 16.51 0.65 51.87 2.04
6 1/4 M 1/2 - - - - 16.71 0.658 52.5 2.07
6 1/2 N 54 17 13 14 16.92 0.666 53.16 2.09
6 3/4 N 1/2 - - - - 17.13 0.674 53.82 2.12
7 O 55 1/4 17 1/4 14 15 1/4 17.35 0.683 54.51 2.15
7 1/4 O 1/2 - - - - 17.45 0.687 54.82 2.16
7 1/2 P 56 1/2 17 3/4 15 16 1/2 17.75 0.699 55.76 2.2
7 3/4 P 1/2 - - - - 17.97 0.707 56.45 2.22
8 Q 57 3/4 18 16 17 3/4 18.19 0.716 57.15 2.25
8 1/4 Q 1/2 - - - - 18.35 0.722 57.65 2.27
8 1/2 Q 3/4 - 18 1/2 17 - 18.53 0.729 58.21 2.29
8 5/8 R 59 - - 19 18.61 0.733 58.47 2.3
8 3/4 R 1/4 - - - - 18.69 0.736 58.72 2.31
8 7/8 R 1/2 - - - - 18.8 0.74 59.06 2.32
9 R 3/4 - 19 18 - 18.89 0.748 59.34 2.35
9 1/8 S 60 1/4 - - 20 1/4 19.1 0.752 60 2.36
9 1/4 S 1/4 - - - - 19.22 0.757 60.38 2.38
9 3/8 S 1/2 - - - - 19.31 0.76 60.66 2.39
9 1/2 S 3/4 - 19 1/2 19 - 19.41 0.764 60.98 2.4
9 5/8 T 61 1/2 - - 21 1/2 19.51 0.768 61.29 2.41
9 3/4 T 1/4 - - - - 19.62 0.772 61.64 2.43
10 T 1/2 - 20 20 - 19.84 0.781 62.33 2.45
10 1/4 U 62 3/4 - 21 22 3/4 20.02 0.788 62.89 2.48
10 1/2 U 1/2 - 20 1/4 22 - 20.2 0.797 63.46 2.5
10 5/8 V 63 - - 23 3/4 20.32 0.8 63.84 2.51
10 3/4 V 1/4 - - - - 20.44 0.805 64.21 2.53
11 V 1/2 - 20 3/4 23 - 20.68 0.814 64.97 2.56
11 1/8 W 65 - - 25 20.76 0.817 65.22 2.57
11 1/4 W 1/4 - - - - 20.85 0.821 65.5 2.58
11 3/8 W 1/2 - - - - 20.94 0.824 65.78 2.59
11 1/2 W 3/4 - 21 24 - 21.08 0.83 66.22 2.61
11 5/8 X 66 1/4 - - 26 1/4 21.18 0.834 66.54 2.62
11 3/4 X 1/4 - - - - 21.24 0.836 66.73 2.63
11 7/8 X 1/2 - - - - 21.3 0.839 66.92 2.64
12 Y 67 1/2 21 1/4 25 27 1/2 21.49 0.846 67.51 2.66
12 1/4 Y 1/2 - - - - 21.69 0.854 68.14 2.68
12 1/2 Z 68 3/4 21 3/4 26 28 3/4 21.89 0.862 68.77 2.71
12 3/4 Z +1/2 - - - - 22.1 0.87 69.43 2.73
13 Z+1 - 22 27 - 22.33 0.879 70.15 2.76
13.5 Z+1.5 - - - - 22.6 0.89 71 2.8
- Z+2 - - - - 22.69 0.893 71.28 2.81
- Z+2.5 - - - - 22.92 0.902 72 2.83
- Z+3 - - - - 23.06 0.908 72.45 2.85
- Z+3.5 - - - - 23.24 0.915 73.01 2.87
- Z+4 - - - - 23.47 0.924 73.73 2.9
- Z+4.5 - - - - 23.55 0.927 73.98 2.91
- Z+5 - - - - 23.87 0.94 74.99 2.95
- Z+6 - - - - 24.27 0.956 76.25 3