RING SIZE CONVERSION CHART
Complements of:
C
ARRERA
C
ASTING
USA
Diameter (mm)
Circumference (mm)
Diameter (in.)
Circumference (in.)
Britain
Europe
Japan
0
11.54
36.25
0.454
1.427
11.9
37.38
0.469
1.472
A
12
37.7
0.472
1.484
0
12.1
38.01
0.476
1.496
A
1
/
2
12.3
38.64
0.484
1.521
B
1
12.37
38.86
0.487
1.530
12.5
39.27
0.492
1.546
B
1
/
2
1 1/4
12.58
39.52
0.495
1.556
12.7
39.9
0.500
1.571
C
1 1/2
12.78
40.15
0.503
1.581
0.15
12.9
40.53
0.508
1.596
C
1
/
2
0.53
1 3/4
13
40.84
0.512
1.608
0.84
1
13.05
41
0.514
1.614
1
13.1
41.15
0.516
1.620
D
1.15
2
13.21
41.5
0.520
1.634
1.5
13.3
41.78
0.524
1.645
D
1
/
2
1.78
13.33
41.88
0.525
1.649
1.88
2
13.37
42
0.526
1.654
2
2 1/4
13.41
42.13
0.528
1.659
2.13
13.5
42.41
0.531
1.670
E
2.41
2 1/2
13.61
42.76
0.536
1.683
2.76
13.66
42.91
0.538
1.689
2.91
3
13.69
43
0.539
1.693
E
1
/
2
3
2 3/4
13.82
43.42
0.544
1.709
3.42
13.9
43.67
0.547
1.719
F
3.67
14
43.98
0.551
1.731
3.98
4
14.01
44
0.552
1.732
4
3
14.05
44.14
0.553
1.738
4.14
14.1
44.3
0.555
1.744
F
1
/
2
4.3
3 1/4
14.24
44.74
0.561
1.761
4.74
14.3
44.92
0.563
1.769
G
4.92
14.32
45
0.564
1.772
5
14.33
45.02
0.564
1.772
5.02
5
3 1/2
14.45
45.4
0.569
1.787
5.4
14.5
45.55
0.571
1.793
G
1
/
2
5.55
14.64
46
0.576
1.811
6
3 3/4
14.65
46.02
0.577
1.812
6.02
14.66
46.06
0.577
1.813
6.06
6
14.7
46.18
0.579
1.818
H
6.18
4
14.86
46.68
0.585
1.838
6.68
14.9
46.81
0.587
1.843
H
1
/
2
6.81
14.96
47
0.589
1.850
7
15
47.12
0.591
1.855
7.12
7
4 1/4
15.07
47.34
0.593
1.864
7.34
15.1
47.44
0.594
1.868
I
7.44
4 1/2
15.27
47.97
0.601
1.889
7.97
15.28
48
0.602
1.890
8
15.3
48.07
0.602
1.893
I
1
/
2
8.07
15.33
48.16
0.604
1.896
8.16
8
4 3/4
15.48
48.63
0.609
1.915
8.63
15.5
48.69
0.610
1.917
J
8.69
15.6
49
0.614
1.929
9
15.66
49.2
0.617
1.937
9.2
9
5
15.7
49.32
0.618
1.942
J
1
/
2
9.32
5
1
/
4
15.9
49.95
0.626
1.967
K
9.95
15.92
50
0.627
1.969
10
16
50.27
0.630
1.979
10.27
10
5
1
/
2
16.1
50.58
0.634
1.991
K
1
/
2
10.58
16.23
51
0.639
2.008
11
5
3
/
4
16.31
51.24
0.642
2.017
L
11.24
16.33
51.3
0.643
2.020
11.3
11
6
16.51
51.87
0.650
2.042
L
1
/
2
11.87
16.55
52
0.652
2.047
12
16.66
52.34
0.656
2.061
12.34
12
16.7
52.46
0.657
2.065
M
12.46
6
1
/
4
16.73
52.56
0.659
2.069
12.56
16.87
53
0.664
2.087
13
16.9
53.09
0.665
2.090
M
1
/
2
13.09
6
1
/
2
16.92
53.16
0.666
2.093
13.16
17
53.41
0.669
2.103
13.41
13
17.1
53.72
0.673
2.115
N
13.72
6
3
/
4
17.14
53.85
0.675
2.120
13.85
17.19
54
0.677
2.126
14
17.3
54.35
0.681
2.140
N
1
/
2
14.35
17.33
54.44
0.682
2.143
14.44
14
7
17.35
54.51
0.683
2.146
14.51
17.5
54.98
0.689
2.165
O
14.98
7
1
/
4
17.56
55
0.691
2.165
15
17.66
55.48
0.695
2.184
15.48
15
17.7
55.61
0.697
2.189
O
1
/
2
15.61
7
1
/
2
17.75
55.76
0.699
2.195
15.76
17.83
56
0.702
2.205
16
17.9
56.23
0.705
2.214
P
16.23
7
3
/
4
17.97
56.45
0.707
2.222
16.45
18
56.55
0.709
2.226
16.55
16
18.1
56.86
0.713
2.239
P
1
/
2
16.86
18.14
57
0.714
2.244
17
8
18.19
57.15
0.716
2.250
17.15
18.3
57.49
0.720
2.263
Q
17.49
18.33
57.59
0.722
2.267
17.59
17
8
1
/
4
18.39
57.77
0.724
2.274
17.77
18.46
58
0.727
2.283
18
18.5
58.12
0.728
2.288
Q
1
/
2
18.12
8
1
/
2
18.59
58.4
0.732
2.299
18.4
18.66
58.62
0.735
2.308
18.62
18
18.7
58
3
/
4
0.736
#VALUE!
R
18
3
/
4
8
3
/
4
18.78
59
0.739
2.323
19
18.9
59.38
0.744
2.338
R
1
/
2
19.38
9
18.99
59.66
0.748
2.349
19.66
19
59.69
0.748
2.350
19.69
19
19.1
60
0.752
2.362
S
20
9
1
/
4
19.22
60.38
0.757
2.377
20.38
19.3
60.63
0.760
2.387
S
1
/
2
20.63
19.33
60.73
0.761
2.391
20.73
20
9
1
/
2
19.41
60.98
0.764
2.401
20.98
19.42
61
0.765
2.402
21
19.5
61.26
0.768
2.412
T
21.26
9
3
/
4
19.63
61.67
0.773
2.428
21.67
19.66
61.76
0.774
2.431
21.76
21
19.7
61.89
0.776
2.437
T
1
/
2
21.89
19.74
62
0.777
2.441
22
10
19.84
62.33
0.781
2.454
22.33
19.9
62.52
0.783
2.461
U
22.52
20
62.83
0.787
2.474
22.83
22
10
1
/
4
20.05
63
0.789
2.480
23
20.1
63.15
0.791
2.486
U
1
/
2
23.15
10
1
/
2
20.24
63.59
0.797
2.504
23.59
20.3
63.77
0.799
2.511
V
23.77
20.33
63.87
0.800
2.515
23.87
23
20.37
63.99
0.802
2.519
23.99
10
3
/
4
20.46
64.28
0.806
2.531
24.28
20.5
64.4
0.807
2.535
V
1
/
2
24.4
20.66
64.91
0.813
2.556
24.91
24
11
20.68
64.97
0.814
2.558
24.97
20.69
65
0.815
2.559
W
25
11
1
/
4
20.88
65.6
0.822
2.583
25.6
20.9
65.66
0.823
2.585
W
1
/
2
25.66
21
65.97
0.827
2.597
25.97
25
21.01
66
0.827
2.598
26
11
1
/
2
21.08
66.22
0.830
2.607
26.22
21.1
66.29
0.831
2.610
X
26.29
10
3
/
4
21.3
66.92
0.839
2.635
X
1
/
2
26.92
21.33
67.01
0.840
2.638
27.01
26
12
21.49
67.51
0.846
2.658
Y
27.51
21.65
68.02
0.852
2.678
28.02
21.66
68.05
0.853
2.679
28.05
27
12
1
/
4
21.71
68.2
0.855
2.685
Y
1
/
2
28.2
12
1
/
2
21.89
68.77
0.862
2.707
Z
28.77
21.96
68.99
0.865
2.716
28.99
22
69.12
0.866
2.721
29.12
28
22.1
69.43
0.870
2.733
Z
1
/
2
29.43
12
3
/
4
22.12
69.49
0.871
2.736
29.49
22.28
69.99
0.877
2.756
Z+1
29.99
13
22.33
70.15
0.879
2.762
30.15
29
22.5
70.69
0.886
2.783
Z+1
1
/
2
30.69
13
1
/
4
22.54
70.81
0.887
2.788
30.81
22.6
71
0.890
2.795
31
22.66
71.19
0.892
2.803
31.19
30
22.7
71.31
0.894
2.807
Z+2
31.31
13
1
/
2
22.75
71.47
0.896
2.814
31.47
13
3
/
4
22.92
72.01
0.902
2.835
Z+2
1
/
2
32.01
23
72.26
0.906
2.845
32.26
31
23.1
72.57
0.909
2.857
Z+3
32.57
14
23.16
72.76
0.912
2.865
32.76
23.24
73.01
0.915
2.874
33.01
23.3
73.2
0.917
2.882
Z+3
1
/
2
33.2
23.34
73.32
0.919
2.887
33.32
23.33
73.29
0.919
2.885
33.29
32
14
1
/
4
23.37
73.42
0.920
2.891
33.42
23.5
73.83
0.925
2.907
Z+4
33.83
14
1
/
2
23.55
73.98
0.927
2.913
33.98
23.66
74.33
0.931
2.926
34.33
33
23.7
74.46
0.933
2.931
Z+4
1
/
2
34.46
14
3
/
4
23.78
74.71
0.936
2.941
34.71
23.87
74.99
0.940
2.952
34.99
23.9
75.08
0.941
2.956
Z+5
35.08
15
24
75.4
0.945
2.969
35.4
34
24.1
75.71
0.949
2.981
Z+5
1
/
2
35.71
15
1
/
4
24.19
76
0.952
2.992
36
24.3
76.34
0.957
3.006
Z+6
36.34
24.33
76.43
0.958
3.009
36.43
35
15
1
/
2
24.41
76.69
0.961
3.019
36.69
24.51
77
0.965
3.031
Z+6
1
/
2
37
15
3
/
4
24.61
77.31
0.969
3.044
37.31
24.66
77.47
0.971
3.050
37.47
36
24.7
77.6
0.972
3.055
Z+7
37.6
16
24.83
78
0.978
3.071
38
24.9
78.23
0.980
3.080
Z+7
1
/
2
38.23
16
1
/
4
25
78.54
0.984
3.092
38.54
37