Ring Size Conversion Chart
Convert from the ring sizes used in one country or region to the ring sizes used in another country or region.
Diameter and circumference measured in millimeters (mm). convert millimeters
Ring sizes by country, measured in millimeters (mm).
| US / Canada |
UK |
Japan |
Diameter (mm) |
Circumference (mm) |
| 4 |
H 1/2 |
7 |
14.8mm |
46.5mm |
| 4 1/2 |
I 1/2 |
8 |
15.2mm |
48mm |
| 5 |
J 1/2 |
9 |
15.6mm |
49mm |
| 5 1/2 |
L |
10 |
16mm |
50.5mm |
| 6 |
M |
12 |
16.4mm |
52mm |
| 6 1/2 |
N |
13 |
16.8mm |
53mm |
| 7 |
O |
14 |
17.3mm |
54.5mm |
| 7 1/2 |
P |
15 |
17.7mm |
55.5mm |
| 8 |
Q |
16 |
18.1mm |
57mm |
| 8 1/2 |
Q 1/2 |
17 |
18.5mm |
58mm |
| 9 |
R 1/2 |
18 |
18.9mm |
59.5mm |
| 9 1/2 |
S 1/2 |
20 |
19.3mm |
61mm |
| 10 |
T 1/2 |
21 |
19.7mm |
62mm |
| 10 1/2 |
U 1/2 |
22 |
20.1mm |
63.5mm |
| 11 |
V 1/2 |
24 |
20.6mm |
64.5mm |
| 11 1/2 |
W 1/2 |
25 |
21mm |
66mm |
| 12 |
Y |
26 |
21.4mm |
67.5mm |
| 12 1/2 |
Z |
27 |
21.8mm |
68.5mm |
| 13 |
Z+1 |
28 |
22.2mm |
70mm |
| 13 1/2 |
Z+2 |
29 |
22.6mm |
71mm |
| 14 |
Z+3 |
31 |
23mm |
72.5mm |
| 14 1/2 |
Z+4 |
32 |
23.4mm |
74mm |
| 15 |
Z+5 |
33 |
23.9mm |
75mm |