International ring size Conversion table
USA & Canada
Diameter
(inch)
Diameter
(mm)
Metric
(mm)
British
French
German
Japan
Swiss
0
0.39
9.91
-
00
0.422
10.72
-
000
0.454
11.53
-
1/4
0.474
11.95
A
3/4
0.482
12.18
A 1/2
1
0.487
12.37
38.9
B
1
1 1/4
-
12.6
39.6
B 1/2
1 1/2
0.503
12.78
40.2
C
1 3/4
-
13
40.8
C 1/2
2
0.52
13.21
41.5
D
41 1/2
13 1/2
2
1 1/2
2 1/4
-
13.41
42.1
D 1/2
-
-
2 1/2
0.536
13.61
42.7
E
42 3/4
13 3/4
3
2 3/4
2 3/4
-
13.83
43.4
E 1/2
-
-
3
0.553
14.05
44
F
44
14
4
4
3 1/8
-
14.15
44.3
F 1/2
-
-
3 1/4
-
14.25
44.6
-
-
-
3 3/8
-
14.36
44.9
G
45 1/4
-
5
5 1/4
3 1/2
0.569
14.45
45.2
-
-
14 1/2
3 5/8
-
14.56
45.6
G 1/2
-
6
3 3/4
-
14.65
45.9
H
46 1/2
6 1/2
4
0.585
14.86
46.5
H 1/2
-
15
7
4 1/4
-
15.04
47.1
I
47 3/4
7 3/4
4 1/2
0.601
15.27
47.8
I 1/2
-
15 1/4
8
4 5/8
-
15.4
48.1
J
49
15 1/2
9
4 3/4
-
15.53
48.4
-
-
5
0.618
15.7
49
J 1/2
-
15 3/4
9
5 1/8
-
15.8
49.3
K
50
10
5 1/4
-
15.9
49.6
-
-
5 3/8
-
16
50
K 1/2
-
10
5 1/2
0.634
16.1
50.3
L
51 3/4
16
11 3/4
5 3/4
-
16.3
50.9
-
-
5 7/8
-
16.41
51.3
L 1/2
-
6
0.65
16.51
51.5
M
52 3/4
16 1/2
12
12 3/4
6 1/4
-
16.71
52.2
M 1/2
-
6 1/2
0.666
16.92
52.8
N
54
17
13
14
6 3/4
-
17.13
53.4
N 1/2
-
7
0.683
17.35
54
O
55 1/4
17 1/4
14
15 1/4
7 1/4
-
17.45
54.7
O 1/2
-
7 1/2
0.699
17.75
55.3
P
56 1/2
17 3/4
15
16 1/2
7 3/4
-
17.97
55.9
P 1/2
-
8
0.716
18.19
56.6
Q
57 3/4
18
16
17 3/4
8 1/4
-
18.35
57.2
Q 1/2
-
8 1/2
0.732
18.53
57.8
-
-
18 1/2
17
8 5/8
-
18.61
58.4
R
59
19
8 3/4
-
18.69
58.4
-
-
8 7/8
-
18.8
59
R 1/2
-
9
0.748
18.89
59.1
-
-
19
18
9 1/8
-
19.1
59.4
S
60 1/4
20 1/4
9 1/4
-
19.22
59.7
-
-
9 3/8
-
19.31
60
S 1/2
-
9 1/2
0.764
19.41
60.3
-
-
19 1/2
19
9 5/8
-
19.51
60.6
T
61 1/2
21 1/2
9 3/4
-
19.62
60.9
-
-
10
0.781
19.84
61.6
T 1/2
-
20
20
10 1/4
-
20.02
62.2
U
62 3/4
21
22 3/4
10 1/2
0.797
20.2
62.8
U 1/2
-
20 1/4
22
10 5/8
-
20.32
63.1
V
63
23 3/4
10 3/4
-
20.44
63.5
-
-
11
0.814
20.68
64.1
V 1/2
-
20 3/4
23
11 1/8
-
20.76
64.3
W
65
25
11 1/4
-
20.85
64.7
-
-
11 3/8
-
20.94
65
W 1/2
-
11 1/2
-
21.08
65.3
-
-
21
24
11 5/8
0.83
21.18
65.7
X
66 1/4
26 1/4
11 3/4
-
21.24
66
-
-
11 7/8
-
21.3
66.3
X 1/2
-
12
0.846
21.49
66.6
Y
67 1/2
21 1/4
25
27 1/2
12 1/4
-
21.69
67.2
Y 1/2
-
12 1/2
0.862
21.89
67.9
Z
68 3/4
21 3/4
26
28 3/4
12 3/4
-
22.1
68.5
Z 1/2
-
13
0.879
22.33
69.1
-
-
22
27
Most common sizes for lady's is 17 mm and for the gentleman 19 mm.
Grafiek voor gewichtsvergelijking
Pt.
F.G.
22kt
18kt
14kt
10kt
9kt
F.S.
Stg
Pt.
1.00
0.90
0.82
0.70
0.60
0.53
0.53
0.49
0.48
F.G.
1.11
1.00
0.91
0.78
0.67
0.59
0.58
0.54
0.54
22kt
1.22
1.10
1.00
0.86
0.73
0.65
0.65
0.60
0.59
18kt
1.42
1.28
1.16
1.00
0.85
0.76
0.75
0.69
0.68
14kt
1.66
1.50
1.36
1.17
1.00
0.89
0.88
0.81
0.80
10kt
1.88
1.69
1.54
1.32
1.13
1.00
0.99
0.92
0.90
9kt
1.90
1.71
1.56
1.34
1.14
1.01
1.00
0.93
0.92
F.S.
2.04
1.84
1.68
1.44
1.23
1.09
1.08
1.00
0.99
Stg
2.07
1.87
1.70
1.46
1.25
1.11
1.09
1.01
1.00
1993 - TITANIUM
