Ring Size Chart

US Size	UK Size	EU Size	Swiss Size	Diameter (mm)	Circumference (mm)
2.0	D	42	1.5	13.2	41.5
2.5	E	43	2.75	13.6	42.8
3.0	F	44	4.0	14.0	44.0
3.5	G½	45	5.2	14.4	45.2
4.0	H½	46	6.5	14.8	46.5
4.5	I½	48	7.7	15.2	47.7
5.0	J½	49	9.0	15.6	49.0
5.5	K½	50	10.2	16.0	50.2
6.0	L½	52	11.5	16.4	51.5
6.5	M½	53	12.7	16.8	52.7
7.0	N½	54	14.0	17.2	54.0
7.5	O½	56	15.2	17.6	55.2
8.0	P½	57	16.5	18.0	56.5
8.5	Q½	58	17.7	18.4	57.7
9.0	R½	59	19.0	18.8	59.0
9.5	S½	60	20.2	19.2	60.2
10.0	T½	62	21.5	19.6	61.5
10.5	U½	63	22.7	20.0	62.7
11.0	V½	64	24.0	20.4	64.0
11.5	W½	65	25.2	20.8	65.2
12.0	X½	67	26.5	21.2	66.5

How to measure the diameter of your ring