UK to ISO Ring Size Chart

UK US ISO
F 3 44
G 3.5 46
H 4 47
I 4.5 48
J 5 49
K 5.5 51
L 6 52
M 6.5 53
N 7 54
O 7.5 56
P 8 57
Q 8.5 58
R 9 60
S 9.5 61
T 10 62
U 10.5 63
V 11 65
W 11.5 66
X 12 67
Y 12.5 68
Z 13 70
Z1 13.5 71
Z2 14 72

ISO sizes represent inner circumference in millimeters — the international standard for ring sizing.