About sizes

UK sizeDiameter (mm)

Circumference (mm)

I15,29 48,0
I+15,3948,3
J15,4948,7
J+15,70 49,3
K15,9050,0
K+16,1050,6
L16,3151,2
L+16,5151,9
M16,7152,5
M+16,9253,1
N 17,1253,8
N+17,3254,4
O17,5355,1
O+17,7355,7
P17,9356,3
P+18,1457,0
Q18,3457,6
Q+18,5458,3
R18,7558,9
R+18,9559,5
S19,1560,2
S+19,3560,8
T19,5661,4
T+19,7662,1
U19,9662,7
U+20,1763,4
V20,3764,0
V+20,5764,6
W20,7865,3
W+20,9865,9
X21,1866,6
X+21,3967,2
Y21,5967,8
Y+21,6968,1
Z21,7968,5
Z+22,0069,1