Ring Size Comparison Chart

by International Gem Society

US Standard (Also Canada)	Diameter in Inches	British Equivalent	French Equivalent	German Equivalent	Swiss Equivalent	Japanese Equivalent
0	.454	–	–	–	–	–
1/2	–	A	–	–	–	–
1	.487	B	–	–	–	1
1 1/2	.503	C	–	–	–	–
2	.520	D	41 ½	13 ¼	1 ½	2
2 1/2	.536	E	42 ¾	13 ¾	2 ¾	3
3	.553	F	44	14	4	4
3 3/8	–	G	45 ½	–	5 ½	5
3 1/2	.569	–	–	14 ½	–	–
3 3/4	–	H	46 ½	–	6 ½	–
4	.585	H ½	–	15	–	7
4 1/4	–	I	47 ¾	–	7 ¾	–
4 7/8	–	J	49	–	9	–
5	.618	J ½	–	15 ¾	–	9
5 1/8	–	K	50	–	10	–
5 1/2	.634	L	51 ¾	16	11 ¾	–
6	.650	M	52 ¾	16 ½	12 ¾	12
6 1/2	.666	N	54	17	14	13
7	.683	O	55 ¼	17 ¼	15 ¼	14
7 1/4	.699	P	56 ½	17 ¾	16 ½	15
8	.716	Q	57 ¾	18	17 ¾	16
8 1/2	.732	–	–	18 ½	–	17
8 5/8	–	R	59	–	19	–
9	.748	–	–	19	–	18
9 1/8	–	S	60 ¼	–	20 ¼	–
9 1/4	.764	–	–	19 ½	–	19
9 5/8	–	T	61 ½	–	21 ½	–
10	.781	T ½	–	20	–	20
10 1/4	–	U	62 ¾	–	22 ¾	21
10 1/2	.797	U ½	–	20 ¼	–	22
10 5/8	–	V	63 ¾	–	23 ¾	–
11	.814	V ½	–	20 ¾	–	23
11 1/8	–	W	65	–	25	–
11 1/2	.830	–	–	21	–	24
11 5/8	–	X	66 ¼	–	26 ¼	–
12	.846	Y	67 ½	21 ¼	27 ½	25
12 1/2	.862	Z	68 ¾	21 ¾	28 ¾	26
13	.879	–	–	22	–	27

Compliments of The International Gem Society

IGS Membership