Ring Size Chart

One table converting ring sizes between the US, UK, European and Asian systems, with the matching diameter and circumference in both inches and millimeters.

Ring size chart

Read the chart using your measured inside diameter or circumference in millimetres, then follow that row to the required sizing system. Do not confuse diameter with circumference, or assume that the same size number means the same fit in every country.

Need to measure first? Follow the ring-size measuring guide or use the on-screen size finder. These conversions are a reference: confirm the seller’s sizing system and the fit of your chosen band before ordering.

Scroll the table sideways to see all regions.

International ring size conversion
US & Canada	UK, Australia, NZ	EU / ISO (approx.)	China & Japan	Inner diameter (mm)	Inner circumference (mm)	Inner diameter (in)	Inner circumference (in)
·	·	37	·	11.6	36.5	0.458	1.438
·	·	37	·	11.8	37.2	0.466	1.463
·	A	38	·	12	37.8	0.474	1.488
·	A 1/2	38	·	12.2	38.4	0.482	1.513
1	B	39	1	12.4	39.1	0.49	1.539
1 1/4	B 1/2	40	·	12.6	39.7	0.498	1.564
1 1/2	C	40	·	12.9	40.4	0.506	1.589
1 3/4	C 1/2	41	·	13.1	41	0.514	1.614
2	D	42	2	13.3	41.6	0.522	1.639
2 1/4	D 1/2	42	·	13.5	42.3	0.53	1.664
2 1/2	E	43	3	13.7	42.9	0.538	1.689
2 3/4	E 1/2	44	·	13.9	43.5	0.546	1.714
3	F	44	4	14.1	44.2	0.554	1.74
3 1/4	F 1/2	45	5	14.3	44.8	0.562	1.765
3 1/2	G	46	·	14.5	45.5	0.57	1.79
3 3/4	G 1/2	46	6	14.7	46.1	0.578	1.815
4	H	47	7	14.9	46.7	0.586	1.84
4 1/4	H 1/2	47	·	15.1	47.4	0.594	1.865
4 1/2	I	48	8	15.3	48	0.602	1.89
4 3/4	J	49	·	15.5	48.7	0.61	1.915
5	J 1/2	49	9	15.7	49.3	0.618	1.941
5 1/4	K	50	·	15.9	49.9	0.626	1.966
5 1/2	K 1/2	51	10	16.1	50.6	0.634	1.991
5 3/4	L	51	·	16.3	51.2	0.642	2.016
6	L 1/2	52	11	16.5	51.8	0.65	2.041
6 1/4	M	53	12	16.7	52.5	0.658	2.066
6 1/2	M 1/2	53	13	16.9	53.1	0.666	2.091
6 3/4	N	54	·	17.1	53.8	0.674	2.116
7	N 1/2	54	14	17.3	54.4	0.682	2.141
7 1/4	O	55	·	17.5	55	0.69	2.167
7 1/2	O 1/2	56	15	17.7	55.7	0.698	2.192
7 3/4	P	56	·	17.9	56.3	0.706	2.217
8	P 1/2	57	16	18.1	56.9	0.714	2.242
8 1/4	Q	58	·	18.3	57.6	0.722	2.267
8 1/2	Q 1/2	58	17	18.5	58.2	0.73	2.292
8 3/4	R	59	·	18.7	58.9	0.738	2.317
9	R 1/2	60	18	18.9	59.5	0.746	2.342
9 1/4	S	60	·	19.2	60.1	0.754	2.368
9 1/2	S 1/2	61	19	19.4	60.8	0.762	2.393
9 3/4	T	61	·	19.6	61.4	0.77	2.418
10	T 1/2	62	20	19.8	62.1	0.778	2.443
10 1/4	U	63	21	20	62.7	0.786	2.468
10 1/2	U 1/2	63	22	20.2	63.3	0.794	2.493
10 3/4	V	64	·	20.4	64	0.802	2.518
11	V 1/2	65	23	20.6	64.6	0.81	2.543
11 1/4	W	65	·	20.8	65.2	0.818	2.569
11 1/2	W 1/2	66	24	21	65.9	0.826	2.594
11 3/4	X	67	·	21.2	66.5	0.834	2.619
12	X 1/2	67	25	21.4	67.2	0.842	2.644
12 1/4	Y	68	·	21.6	67.8	0.85	2.669
12 1/2	Z	68	26	21.8	68.4	0.858	2.694
12 3/4	Z 1/2	69	·	22	69.1	0.866	2.719
13	·	70	27	22.2	69.7	0.874	2.744
13 1/4	Z1	70	·	22.4	70.3	0.882	2.769
13 1/2	·	71	·	22.6	71	0.89	2.795
13 3/4	Z2	72	·	22.8	71.6	0.898	2.82
14	Z3	72	·	23	72.3	0.906	2.845
14 1/4	·	73	·	23.2	72.9	0.914	2.87
14 1/2	Z4	74	·	23.4	73.5	0.922	2.895
14 3/4	·	74	·	23.6	74.2	0.93	2.92
15	·	75	·	23.8	74.8	0.938	2.945
15 1/4	·	75	·	24	75.4	0.946	2.97
15 1/2	·	76	·	24.2	76.1	0.954	2.996
15 3/4	·	77	·	24.4	76.7	0.962	3.021
16	·	77	·	24.6	77.4	0.97	3.046

International ring size conversion