Ring Size Conversion Chart.

Compare UK and US ring sizes with their corresponding diameters and circumferences in mm.

Ring Size Conversion Chart

UK Size US Size Diameter (mm) Circumference (mm)
D 2 13.21 41.5
D 1/2 2.25 13.41 42.13
E 2.5 13.61 42.76
E 1/2 2.75 13.83 43.45
F 2.875 14.05 44.14
F 1/2 3 14.15 44.45
F 3/4 3.125 14.25 44.77
G 3.25 14.36 45.11
G 1/4 3.375 14.45 45.4
G 1/2 3.5 14.56 45.74
H 3.75 14.65 46.02
H 1/2 4 14.86 46.68
I 4.25 15.04 47.25
I 1/2 4.5 15.27 47.97
J 4.75 15.4 48.38
J 1/4 4.875 15.53 48.79
J 1/2 5 15.7 49.32
K 5.25 15.8 49.64
K 1/4 5.375 15.9 49.95
K 1/2 5.5 16 50.27
L 5.75 16.1 50.58
L 1/4 5.875 16.3 51.21
L 1/2 6 16.41 51.55
M 6.25 16.51 51.87
M 1/2 6.5 16.71 52.5
N 6.75 16.92 53.16
N 1/2 7 17.13 53.82
O 7.25 17.35 54.51
O 1/2 7.5 17.45 54.82
P 7.75 17.75 55.76
P 1/2 8 17.97 56.45
Q 8.25 18.19 57.15
Q 1/2 8.5 18.35 57.65
Q 3/4 8.625 18.53 58.21
R 8.75 18.61 58.47
R 1/4 8.875 18.69 58.72
R 1/2 9 18.8 59.06
R 3/4 9.125 18.89 59.34
S 9.25 19.1 60
S 1/4 9.375 19.22 60.38
S 1/2 9.5 19.31 60.66
S 3/4 9.625 19.41 60.98
T 9.75 19.51 61.29
T 1/4 9.875 19.62 61.64
T 1/2 10 19.84 62.33
U 10.25 20.02 62.89
U 1/2 10.5 20.2 63.46
V 10.625 20.32 63.84
V 1/4 10.75 20.44 64.21
V 1/2 11 20.68 64.97
W 11.125 20.76 65.22
W 1/4 11.25 20.85 65.5
W 1/2 11.375 20.94 65.78
W 3/4 11.5 21.08 66.22
X 11.625 21.18 66.54
X 1/4 11.75 21.24 66.73
X 1/2 12 21.3 66.92
Y 12.25 21.49 67.51
Y 1/2 12.375 21.69 68.14
Z 12.5 21.89 68.77

Got questions? Contact our support team anytime.