International Ring Size Conversion Chart

International Ring Size Conversion Chart
Inside Diameter Inside Circumference Sizes
MM Inches MM Inches British & Australian US & Canada French & Russian German Japanese Swiss
9.91 0.39 31.13 1.22 - 0000 - - - -
10.72 0.44 33.68 1.39 - 00 - - - -
11.53 0.45 36.22 1.43 - 0 - - - -
11.95 0.47 37.54 1.49 A ½ - - - -
12.18 0.48 38.26 1.51 A 1/2 ¾ - - - -
12.37 0.49 38.86 1.53 B 1 - - 1 -
12.6 0.5 39.58 1.56 B 1/2 1 1/4 - - - -
12.78 0.5 40.15 1.58 C 1 1/2 - - - -
13 0.51 40.84 1.61 C 1/2 1 3/4 - - - -
13.21 0.52 41.5 1.63 D 2 41.5 13.5 2 1.5
13.41 0.53 42.13 1.66 D 1/2 2 1/4 - - - -
13.61 0.54 42.76 1.68 E 2 1/2 42 3/4 13 3/4 3 2 3/4
13.83 0.54 43.45 1.71 E 1/2 2 3/4 - - - -
14.05 0.55 44.14 1.74 F 3 44 14 4 4
14.15 0.56 44.45 1.75 F 1/2 3.13 - - - -
14.25 0.56 44.77 1.76 F 3/4 3 1/4 - - - -
14.36 0.57 45.11 1.77 G 3 3/8 45 1/4 - 5 5 1/4
14.45 0.57 45.4 1.79 G 1/4 3 1/2 - 14 1/2 - -
14.56 0.57 45.74 1.8 G 1/2 3 5/8 - - 6 -
14.65 0.58 46.02 1.81 H 3.75 46.5 - - 6.5
14.86 0.59 46.68 1.84 H 1/2 4 - 15 7 -
15.04 0.59 47.25 1.86 I 4 1/4 47 3/4 - - 7 3/4
15.27 0.6 47.97 1.89 I 1/2 4 1/2 - 15 1/4 8 -
15.4 0.61 48.38 1.9 J 4 5/8 49 15 1/2 - 9
15.53 0.61 48.79 1.92 J 1/4 4.75 - - - -
15.7 0.62 49.32 1.94 J 1/2 5 - 15 3/4 9 -
15.8 0.62 49.64 1.95 K 5 1/8 50 - - 10
15.9 0.63 49.95 1.97 K 1/4 5 1/4 - - - -
16 0.63 50.27 1.98 K 1/2 5 3/8 - - 10 -
16.1 0.63 50.58 1.99 L 5.5 51.75 16 - 11.75
16.3 0.64 51.21 2.02 L 1/4 5 3/4 - - - -
16.41 0.65 51.55 2.03 L 1/2 5 7/8 - - - -
16.51 0.65 51.87 2.04 M 6 52 3/4 16 1/2 12 12 3/4
16.71 0.66 52.5 2.07 M 1/2 6 1/4 - - - -
16.92 0.67 53.16 2.09 N 6.5 54 17 13 14
17.13 0.67 53.82 2.12 N 1/2 6 3/4 - - - -
17.35 0.68 54.51 2.15 O 7 55 1/4 17 1/4 14 15 1/4
17.45 0.69 54.82 2.16 O 1/2 7 1/4 - - - -
17.75 0.7 55.76 2.2 P 7 1/2 56 1/2 17 3/4 15 16 1/2
17.97 0.71 56.45 2.22 P 1/2 7.75 - - - -
18.19 0.72 57.15 2.25 Q 8 57 3/4 18 16 17 3/4
18.35 0.72 57.65 2.27 Q 1/2 8 1/4 - - - -
18.53 0.73 58.21 2.29 Q 3/4 8 1/2 - 18 1/2 17 -
18.61 0.73 58.47 2.3 R 8 5/8 59 - - 19
18.69 0.74 58.72 2.31 R 1/4 8.75 - - - -
18.8 0.74 59.06 2.32 R 1/2 8 7/8 - - - -
18.89 0.75 59.34 2.35 R 3/4 9 - 19 18 -
19.1 0.75 60 2.36 S 9 1/8 60 1/4 - - 20 1/4
19.22 0.76 60.38 2.38 S 1/4 9 1/4 - - - -
19.31 0.76 60.66 2.39 S 1/2 9.38 - - - -
19.41 0.76 60.98 2.4 S 3/4 9 1/2 - 19 1/2 19 -
19.51 0.77 61.29 2.41 T 9 5/8 61 1/2 - - 21 1/2
19.62 0.77 61.64 2.43 T 1/4 9 3/4 - - - -
19.84 0.78 62.33 2.45 T 1/2 10 - 20 20 -
20.02 0.79 62.89 2.48 U 10.25 62.75 - 21 22.75
20.2 0.8 63.46 2.5 U 1/2 10 1/2 - 20 1/4 22 -
20.32 0.8 63.84 2.51 V 10 5/8 63 - - 23 3/4
20.44 0.81 64.21 2.53 V 1/4 10 3/4 - - - -
20.68 0.81 64.97 2.56 V 1/2 11 - 20 3/4 23 -
20.76 0.82 65.22 2.57 W 11.13 65 - - 25
20.85 0.82 65.5 2.58 W 1/4 11 1/4 - - - -
20.94 0.82 65.78 2.59 W 1/2 11 3/8 - - - -
21.08 0.83 66.22 2.61 W 3/4 11 1/2 - 21 24 -
21.18 0.83 66.54 2.62 X 11 5/8 66 1/4 - - 26 1/4
21.24 0.84 66.73 2.63 X 1/4 11.75 - - - -
21.3 0.84 66.92 2.64 X 1/2 11 7/8 - - - -
21.49 0.85 67.51 2.66 Y 12 67 1/2 21 1/4 25 27 1/2
21.69 0.85 68.14 2.68 Y 1/2 12 1/4 - - - -
21.89 0.86 68.77 2.71 Z 12 1/2 68 3/4 21 3/4 26 28 3/4
22.1 0.87 69.43 2.73 Z +1/2 12.75 - - - -
22.33 0.88 70.15 2.76 Z+1 13 - 22 27 -
22.6 0.89 71 2.8 Z+1.5 13.5 - - - -
22.69 0.89 71.28 2.81 Z+2 - - - - -
22.92 0.9 72 2.83 Z+2.5 - - - - -
23.06 0.91 72.45 2.85 Z+3 - - - - -
23.24 0.92 73.01 2.87 Z+3.5 - - - - -
23.47 0.92 73.73 2.9 Z+4 - - - - -
23.55 0.93 73.98 2.91 Z+4.5 - - - - -
23.87 0.94 74.99 2.95 Z+5 - - - - -
24.27 0.96 76.25 3 Z+6 - - - - -

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