Ring Sizing
US
AU/UK
INNER DIAMETER
0.5
A
12.0 mm
0.75
A1/2
12.2 mm
1
B
12.5 mm
1.25
B1/2
12.7 mm
1.5
C
12.9 mm
1.75
C1/2
13.0 mm
2
D
13.1 mm
2.25
D1/2
13.3 mm
2.5
E
13.5mm
2.75
E1/2
13.7mm
3
F
13.9mm
3.25
F1/2
14.1mm
3.5
G
14.38mm
3.75
G1/2
14.53mm
4
H
14.76mm
4.25
H1/2
14.94mm
4.5
I
15.17mm
4.75
I1/2
15.35 mm
5
J
15.57 mm
5.25
J1/2
15.78 mm
5.5
K
16.0 mm
5.75
K1/2
16.16 mm
6
L
16.38 mm
6.25
L1/2
16.58 mm
6.5
M
16.8 mm
6.75
M1/2
17.0 mm
7
N
17.23 mm
US
AU/UK
INNER DIAMETER
7.25
N1/2
17.4 mm
7.5
O
17.62 mm
7.75
O1/2
17.83 mm
8
P
18.03 mm
8.25
P1/2
18.23 mm
8.5
Q
18.46 mm
8.75
Q1/2
18.63 mm
9
R
18.87 mm
9.25
R1/2
19 mm
9.5
S
19.27 mm
9.75
S1/2
19.47 mm
10
T
19.7 mm
10.25
T1/2
19.86 mm
10.5
U
20.1 mm
10.75
U1/2
20.25 mm
11
V
20.51 mm
11.25
V1/2
20.7 mm
11.5
W
20.9 mm
11.75
W1/2
21.07 mm
12
X
21.3 mm
12.25
X1/2
21.47 mm
12.5
Y
21.77 mm
12.75
Y1/2
21.9 mm
13
Z
22.1 mm
13.25
Z1/2
22.33 mm
Please enquire for larger sizes
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