Ring Size Conversion Chart

International Ring Size Conversion Chart
Inside Diameter		Inside Circumference		Sizes
MM	Inches	MM	Inches	British & Australian	US & Canada	French & Russian	German	Japanese	Swiss
9.91	0.390	31.13	1.220	–	0000	–	–	–	–
10.72	0.442	33.68	1.390	–	00	–	–	–	–
11.53	0.454	36.22	1.430	–	0	–	–	–	–
11.95	0.474	37.54	1.490	A	1/2	–	–	–	–
12.18	0.482	38.26	1.510	A 1/2	3/4	–	–	–	–
12.37	0.487	38.86	1.530	B	1	–	–	1	–
12.60	0.496	39.58	1.560	B 1/2	1-1/4	–	–	–	–
12.78	0.503	40.15	1.580	C	1-1/2	–	–	–	–
13.00	0.512	40.84	1.610	C 1/2	1-3/4	–	–	–	–
13.21	0.520	41.50	1.630	D	2	41-1/2	13-1/2	2	1-1/2
13.41	0.528	42.13	1.660	D 1/2	2-1/4	–	–	–	–
13.61	0.536	42.76	1.680	E	2-1/2	42-3/4	13-3/4	3	2-3/4
13.83	0.544	43.45	1.710	E 1/2	2-3/4	–	–	–	–
14.05	0.553	44.14	1.740	F	3	44	14	4	4
14.15	0.557	44.45	1.750	F 1/2	3-1/8	–	–	–	–
14.25	0.561	44.77	1.760	F 3/4	3-1/4	–	–	–	–
14.36	0.565	45.11	1.770	G	3-3/8	45-1/4	–	5	5-1/4
14.45	0.569	45.40	1.790	G 1/4	3-1/2	–	14-1/2	–	–
14.56	0.573	45.74	1.800	G 1/2	3-5/8	–	–	6	–
14.65	0.577	46.02	1.810	H	3-3/4	46-1/2	–	–	6-1/2
14.86	0.585	46.68	1.840	H 1/2	4	–	15	7	–
15.04	0.592	47.25	1.860	I	4-1/4	47-3/4	–	–	7-3/4
15.27	0.601	47.97	1.890	I 1/2	4-1/2	–	15-1/4	8	–
15.40	0.606	48.38	1.900	J	4-5/8	49	15-1/2	–	9
15.53	0.611	48.79	1.920	J 1/4	4-3/4	–	–	–	–
15.70	0.618	49.32	1.940	J 1/2	5	–	15-3/4	9	–
15.80	0.622	49.64	1.950	K	5-1/8	50	–	–	10
15.90	0.626	49.95	1.970	K 1/4	5-1/4	–	–	–	–
16.00	0.630	50.27	1.980	K 1/2	5-3/8	–	–	10	–
16.10	0.634	50.58	1.990	L	5-1/2	51-3/4	16	–	11-3/4
16.30	0.642	51.21	2.020	L 1/4	5-3/4	–	–	–	–
16.41	0.646	51.55	2.030	L 1/2	4-7/8	–	–	–	–
16.51	0.650	51.87	2.040	M	6	52-3/4	16-1/2	12	12-3/4
16.71	0.658	52.50	2.070	M 1/2	6-1/4	–	–	–	–
16.92	0.666	53.16	2.090	N	6-1/2	54	17	13	14
17.13	0.674	53.82	2.120	N 1/2	6-3/4	–	–	–	–
17.35	0.683	54.51	2.150	O	7	55-1/4	17-1/4	14	15-1/4
17.45	0.687	54.82	2.160	O 1/2	7-1/4	–	–	–	–
17.75	0.699	55.76	2.200	P	7-1/2	56-1/2	17-3/4	15	16-1/2
17.97	0.707	56.45	2.220	P 1/2	7-3/4	–	–	–	–
18.19	0.716	57.15	2.250	Q	8	57-3/4	18	16	17-3/4
18.35	0.722	57.65	2.270	Q 1/2	8-1/4	–	–	–	–
18.53	0.729	58.21	2.290	Q 3/4	8-1/2	–	18-1/2	17	–
18.61	0.733	58.47	2.300	R	8-5/8	59	–	–	19
18.69	0.736	58.72	2.310	R 1/4	8-3/4	–	–	–	–
18.80	0.740	59.06	2.320	R 1/2	8-7/8	–	–	–	–
18.89	0.748	59.34	2.350	R 3/4	9	–	19	18	–
19.10	0.752	60.00	2.360	S	9-1/8	60-1/4	–	–	20-1/4
19.22	0.757	60.38	2.380	S 1/4	9-1/4	–	–	–	–
19.31	0.760	60.66	2.390	S 1/2	9-3/8	–	–	–	–
19.41	0.764	60.98	2.400	S 3/4	9-1/2	–	19-1/2	19	–
19.51	0.768	61.29	2.410	T	9-5/8	61-1/2	–	–	21-1/2
19.62	0.772	61.64	2.430	T 1/4	9-3/4	–	–	–	–
19.84	0.781	62.33	2.450	T 1/2	10	–	20	20	–
20.02	0.788	62.89	2.480	U	10-1/4	62-3/4	–	21	22-3/4
20.20	0.797	63.46	2.500	U 1/2	10-1/2	–	20-1/4	22	–
20.32	0.800	63.84	2.510	V	10-5/8	63	–	–	23-3/4
20.44	0.805	64.21	2.530	V 1/4	10-3/4	–	–	–	–
20.68	0.814	64.97	2.560	V 1/2	11	–	20-3/4	23	–
20.76	0.817	65.22	2.570	W	11-1/8	65	–	–	25
20.85	0.821	65.50	2.580	W 1/4	11-1/4	–	–	–	–
20.94	0.824	65.78	2.590	W 1/2	11-3/8	–	–	–	–
21.08	0.830	66.22	2.610	W 3/4	11-1/2	–	21	24	–
21.18	0.834	66.54	2.620	X	11-5/8	66-1/4	–	–	26-1/4
21.24	0.836	66.73	2.630	X 1/4	11-3/4	–	–	–	–
21.30	0.839	66.92	2.640	X 1/2	11-7/8	–	–	–	–
21.49	0.846	67.51	2.660	Y	12	67-1/2	21-1/4	25	27-1/2
21.69	0.854	68.14	2.680	Y 1/2	12-1/4	–	–	–	–
21.89	0.862	68.77	2.710	Z	12-1/2	68-3/4	21-3/4	26	28-3/4
22.10	0.870	69.43	2.730	Z +1/2	12-3/4	–	–	–	–
22.33	0.879	70.15	2.760	Z+1	13	–	22	27	–
22.60	0.890	71.00	2.800	Z+1.5	13-1/2	–	–	–	–
22.69	0.893	71.28	2.810	Z+2	–	–	–	–	–
22.92	0.902	72.00	2.830	Z+2.5	–	–	–	–	–
23.06	0.908	72.45	2.850	Z+3	–	–	–	–	–
23.24	0.915	73.01	2.870	Z+3.5	–	–	–	–	–
23.47	0.924	73.73	2.900	Z+4	–	–	–	–	–
23.55	0.927	73.98	2.910	Z+4.5	–	–	–	–	–
23.87	0.940	74.99	2.950	Z+5	–	–	–	–	–
24.27	0.956	76.25	3.000	Z+6	–	–	–	–	–