| Ring Size Equivalents |
| U.S. & Canada |
Inside
Diameter |
Inside
Circumference |
Great Britain |
France |
Germany |
Japan |
Switzerland |
| 3-1/2 |
... |
... |
... |
... |
14-1/2 |
... |
... |
| 3-3/4 |
... |
... |
H |
46-1/2 |
... |
6-1/2 |
6-1/2 |
| 4 |
16 mm |
50 mm |
H-1/2 |
... |
15 |
7 |
... |
| 4-1/4 |
... |
... |
I |
47-3/4 |
... |
... |
7-3/4 |
| 4-1/2 |
... |
... |
I-1/2 |
... |
15-1/4 |
8 |
... |
| 4-3/4 |
... |
|
J |
49 |
... |
... |
9 |
| 5 |
17 mm |
53 mm |
J-1/2 |
... |
15-3/4 |
9 |
... |
| 5-1/4 |
... |
... |
K |
50 |
... |
... |
10 |
| 5-1/2 |
... |
... |
L |
51-3/4 |
16 |
... |
11-3/4 |
| 5-3/4 |
... |
... |
L-1/2 |
... |
... |
11 |
... |
| 6 |
17.5 mm |
55 mm |
M |
52-3/4 |
16-1/2 |
12 |
12-3/4 |
| 6-1/2 |
... |
... |
N |
54 |
17 |
13 |
14 |
| 7 |
18 mm |
57 mm |
O |
55-1/4 |
17-1/4 |
14 |
15-1/4 |
| 7-1/2 |
... |
... |
P |
56-1/2 |
17-3/4 |
15 |
16-1/2 |
| 8 |
19 mm |
60 mm |
Q |
57-3/4 |
18 |
16 |
17-3/4 |
| 8-1/2 |
... |
... |
... |
... |
18-1/2 |
17 |
... |
| 8-3/4 |
... |
... |
R |
59 |
... |
... |
19 |
| 9 |
20 mm |
63 mm |
... |
... |
19 |
18 |
... |
| 9-1/4 |
... |
... |
S |
60-1/4 |
... |
... |
20-1/4 |
| 9-1/2 |
... |
... |
... |
... |
19-1/2 |
19 |
... |
| 9-3/4 |
... |
... |
T |
61-1/2 |
... |
... |
21-1/2 |
| 10 |
21 mm |
66 mm |
T-1/2 |
... |
20 |
20 |
... |
| 10-1/4 |
... |
... |
U |
62-3/4 |
... |
21 |
22-3/4 |
| 10-1/2 |
... |
... |
U-1/2 |
... |
20-1/4 |
22 |
... |
| 10-3/4 |
... |
... |
V |
63-3/4 |
... |
... |
23-3/4 |
| 11 |
21.5 mm |
68 mm |
V-1/2 |
... |
20-3/4 |
23 |
... |
| 11-1/4 |
... |
... |
W |
65 |
... |
... |
25 |
| 11-1/2 |
... |
... |
... |
... |
21 |
24 |
... |
| 11-3/4 |
... |
... |
X |
66-1/4 |
... |
... |
26-1/4 |
| 12 |
22.5 mm |
71 mm |
Y |
67-1/2 |
21-1/4 |
25 |
27-1/2 |
| 12-1/2 |
... |
... |
Z |
68-3/4 |
21-3/4 |
26 |
28-3/4 |
| 13 |
23 mm |
73 mm |
... |
... |
22 |
27 |
... |
WIRE SIZE CONVERSION CHART
GAUGE 10 12 14 16 18 20 22 24 26 28 30
INCHES .102 .080 .064 .040 .050 .032 .025 .020 .016 .013 .010
MM 2.59 2.05 1.63 1.29 1.02 .813 .643 .511 .404 .320 .254 | 
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