United States · 22 sizes

US / Canada Ring Size Chart.

Numeric with half sizes, roughly 3 to 13½.

Every row is computed from inner circumference, so the diameter and the equivalents in other systems are consistent all the way down.

US / Canada	Diameter	Circumference	Indian	EU / ISO 8653	UK / Australia	Japan / China	Swiss
3	14.05 mm	44.1 mm	4	44	F½	5	4
3½	14.46 mm	45.4 mm	5	45	G½	6	5
4	14.87 mm	46.7 mm	7	47	H½	7	7
4½	15.27 mm	48.0 mm	8	48	I½	9	8
5	15.68 mm	49.3 mm	9	49	J½	10	9
5½	16.08 mm	50.5 mm	11	51	K½	12	11
6	16.49 mm	51.8 mm	12	52	L½	13	12
6½	16.89 mm	53.1 mm	14	53	M½	14	13
7	17.30 mm	54.3 mm	15	54	N½	16	14
7½	17.71 mm	55.6 mm	17	56	O½	17	16
8	18.11 mm	56.9 mm	18	57	P½	19	17
8½	18.52 mm	58.2 mm	19	58	Q½	20	18
9	18.92 mm	59.5 mm	21	59	R½	21	19
9½	19.33 mm	60.7 mm	22	61	S½	23	21
10	19.74 mm	62.0 mm	24	62	T½	24	22
10½	20.14 mm	63.3 mm	25	63	U½	25	23
11	20.55 mm	64.5 mm	27	65	V½	27	25
11½	20.95 mm	65.8 mm	28	66	W½	—	26
12	21.36 mm	67.1 mm	30	67	X½	—	27
12½	21.76 mm	68.4 mm	—	68	Y½	—	—
13	22.17 mm	69.7 mm	—	—	—	—	—
13½	22.58 mm	70.9 mm	—	—	—	—	—

Convert US / Canada to another system

A jeweller's own chart takes precedence over this one — makers differ by a fraction of a size and a proper mandrel beats a paper strip. Fingers also swell through the day and in heat, so measure in the evening. How to measure at home →