Ring Size Conversion Chart
Finger size Internal diameter
British European mm ins Continental American Japanese
(French) (German) (Swiss)
A 12.065 0.4750 1/2
38 12.096 0.4762
A1/2 12.263 0.4828 3/4
39 12.414 0.4887
B 12.459 0.9050 1
B1/2 12.657 0.4983 1 1/4
40 12.733 0.5013
C 12.852 0.5060 1 1/2
C1/2 41 13.051 0.5138 1 3/4
D 13.246 0.5215 1 2
42 13.369 0.5263
D1/2 13.444 0.5293 2 2 1/4
E 13.640 0.5370 2 1/2
43 13.687 0.5389
E1/2 13.838 0.5448 3 2 3/4
44 14.006 0.5514
F 14.034 0.5525 4 3 4
F1/2 14.232 0.5603 3 1/4
45 14.324 0.5639
G 14.427 0.5680 5 3 1/4 5
G1/2 14.625 0.5758 3 1/2
46 14.642 0.5765 6
H 14.821 0.5835 6 3 3/4
47 14.961 0.5890
H1/2 15.019 0.5913 4 7
I 15.215 0.5990 7 4 1/4
48 15.279 0.6015
I1/2 15.413 0.6068 8 4 1/2 8
49 15.597 0.6141
J 15.608 0.6145 4 3/4
J1/2 15.806 0.6223 9 5 9
50 15.916 0.6266
K 16.002 0.6300 10 5 1/4
K1/2 16.200 0.6378 5 1/2 10
51 16.234 0.6391
L 16.396 0.6455 11 5 3/4 11
52 16.552 0.6517
L1/2 16.594 0.6533 6
M 16.789 0.6610 12 6 1/4 12
53 16.871 0.6642
M1/2 16.988 0.6688 13 6 1/2
N 17.183 0.6765 6 3/4 13
54 17.189 0.6767
N1/2 17.381 0.6843 14 7
55 17.507 0.6893
O 17.577 0.6920 15 7 14
O1/2 17.775 0.6998 7 1/4
P 17.971 0.7975 16 7 1/2 15
57 18.144 0.7143
P1/2 18.169 0.7153 7 3/4
Q 18.364 0.7230 17 8 16
58 18.462 0.7269
Q1/2 18.562 0.7308 18 8 1/4 17
R 18.758 0.7385 8 1/2
59 18.780 0.7394
R1/2 18.956 0.7463 19 8 3/4
60 19.098 0.7519
S 19.152 0.7540 20 9 18
S1/2 19.350 0.7618 9 1/4
61 19.416 0.7644
T 19.545 0.7695 21 9 1/2 19
62 19.736 0.7770
T1/2 19.741 0.7772 22 9 3/4 20
U 19.930 0.7850 10 21
63 20.054 0.7895
U1/2 20.137 0.7928 23 10 1/4 22
V 20.333 0.8850 24 10 1/2
64 20.372 0.8020
V1/2 20.531 0.8083 23
65 20.690 0.8146 10 3/4
W 20.726 0.8160 25 11
W1/2 20.925 0.8238 11 1/4
66 21.008 0.8271
X 21.120 0.8315 26 11 1/2 24
X1/2 21.318 0.8393 11 3/4
67 21.326 0.8396
Y 21.514 0.8470 12 25
68 21.645 0.8522
Y1/2 21.712 0.8548 12 1/4
Z 21.908 0.8625 12 1/2 26
69 21.963 0.8647
Z1/2 22.106 0.8703 27
Z+1 22.301 0.8780 12 3/4
Z+2 70 22.695 0.8935 13
Z+3 71 23.089 0.9090 13 1/2
Z+4 72 14
Z+5 73 14 1/4
Z+6 74 14 1/2
Z+7 75 15
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