We use standard US sizing. Please use the table below to determine your size.

Diameter (mm)	Circumference (mm)	US	UK	French/German	Italian
15.1	47.44	4	H½	47.5	7.5
15.3	48.07	4.25	I	48	8
15.5	48.69	4.5	I½	48.5	8.5
15.7	49.32	4.75	J	49.5	9.5
15.9	49.95	5	J½	50	10
16.1	50.58	5.25	K	50.5	10.5
16.3	51.21	5.5	K½	51	11
16.5	51.84	5.75	L	52	12
16.7	52.46	6	L½	52.5	12.5
16.9	53.09	6.25	M	53	13
17.1	53.72	6.5	M½	54	14
17.3	54.35	6.75	N	54.5	14.5
17.5	54.98	7	N½	55	15
17.7	55.61	7.25	O	55.75	15.75
17.9	56.23	7.5	O½	56.25	16.25
18.1	56.86	7.75	P	57	17
18.3	57.49	8	P½	57.25	17.25
18.5	58.12	8.25	Q	58	18
18.7	58.75	8.5	Q½	58.5	18.5
18.9	59.38	8.75	R	59.5	19.5
19.1	60	9	R½	60	20
19.3	60.63	9.25	S	60.5	20.5
19.5	61.26	9.5	S½	61.25	21.25
19.7	61.89	9.75	T	62	22
19.9	62.52	10	T½	62.5	22.5
20.1	63.15	10.5	U	63	23
20.3	63.77	10.5	U½	64	24
20.5	64.4	10.75	V	64.25	24.25
20.7	65.03	11	V½	65	25