This is intended to serve as an approximate guide comparing ring sizes.
UK
sizes |
European
sizes |
USA
sizes |
Continental
sizes |
Internal
Ring diameter (MM) |
K |
50 |
5
¼ |
10 |
16.0 |
L |
51 |
5
¾ |
11 |
16.4 |
M |
52 |
6
¼ |
12 |
16.8 |
N |
53 |
6
¾ |
13.5 |
17.2 |
O |
55 |
7 |
15 |
17.6 |
P |
56 |
7
½ |
16 |
18.0 |
Q |
57 |
8 |
17 |
18.4 |
R |
59 |
8
½ |
18.5 |
18.8 |
S |
60 |
9 |
20 |
19.2 |
T |
61 |
9
½ |
21 |
19.5 |
U |
62 |
10 |
22.5 |
19.9 |
V |
64 |
10
½ |
24 |
20.3 |
W |
65 |
11 |
25 |
20.7 |
X |
66 |
11
½ |
26 |
21.1 |
Y |
67 |
12 |
|
21.5 |
Z |
68 |
12
½ |
|
21.9 |
Z +1 |
69 |
|
|
22.3 |
Z +2 |
70 |
|
|
22.7 |