Ring Size Charts

US/Canada Standard	UK, Irish, Australia	Japan	Swiss	Inside Diameter inches mm		Inside Circumference inches mm
0	-	-	-	0.458	11.6	1.438	36.5
1/4	-	-	-	0.466	11.8	1.463	37.2
1/2	A	-	-	0.474	12.0	1.488	37.8
3/4	A-1/2	-	-	0.482	12.2	1.513	38.4
1	B	1	-	0.490	12.4	1.539	39.1
1-1/4	B-1/2	-	-	0.498	12.6	1.564	39.7
1-1/2	C	-	-	0.506	12.9	1.589	40.4
1-3/4	C-1/2	-	-	0.514	13.1	1.614	41.0
2	D	2	1-1/2	0.522	13.3	1.639	41.6
2-1/4	D-1/2	-	-	0.53	13.5	1.664	42.3
2-1/2	E	3	2-3/4	0.538	13.7	1.689	42.9
2-3/4	E-1/2	-	-	0.546	13.9	1.714	43.5
3	F	4	4	0.554	14.1	1.74	44.2
3-1/4	F-1/2	5	5-1/4	0.562	14.3	1.765	44.8
3-1/2	G	-	-	0.57	14.5	1.79	45.5
3-3/4	G-1/2	6	6-1/2	0.578	14.7	1.815	46.1
4	H	7	-	0.586	14.9	1.84	46.7
4-1/4	H-1/2	-	7-3/4	0.594	15.1	1.865	47.4
4-1/2	I	8	-	0.602	15.3	1.89	48.0
4-3/4	J	-	9	0.61	15.5	1.915	48.7
5	J-1/2	9	-	0.618	15.7	1.941	49.3
5-1/4	K	-	10	0.626	15.9	1.966	49.9
5-1/2	K-1/2	10	-	0.634	16.1	1.991	50.6
5-3/4	L	-	11-3/4	0.642	16.3	2.016	51.2
6	L-1/2	11	12-3/4	0.65	16.5	2.041	51.8
6-1/4	M	12	-	0.658	16.7	2.066	52.5
6-1/2	M-1/2	13	14	0.666	16.9	2.091	53.1
6-3/4	N	-	-	0.674	17.1	2.116	53.8
7	N-1/2	14	15-1/4	0.682	17.3	2.141	54.4
7-1/4	O	-	-	0.69	17.5	2.167	55.0
7-1/2	O-1/2	15	16-1/2	0.698	17.7	2.192	55.7
7-3/4	P	-	-	0.706	17.9	2.217	56.3
8	P-1/2	16	17-3/4	0.714	18.1	2.242	56.9
8-1/4	Q	-	-	0.722	18.3	2.267	57.6
8-1/2	Q-1/2	17	-	0.73	18.5	2.292	58.2
8-3/4	R	-	19	0.738	18.7	2.317	58.9
9	R-1/2	18	-	0.746	18.9	2.342	59.5
9-1/4	S	-	20-1/4	0.754	19.2	2.368	60.1
9-1/2	S-1/2	19	-	0.762	19.4	2.393	60.8
9-3/4	T	-	21-1/2	0.77	19.6	2.418	61.4
10	T-1/2	20	-	0.778	19.8	2.443	62.1
10-1/4	U	21	-	0.786	20.0	2.468	62.7
10-1/2	U-1/2	22	22-3/4	0.794	20.2	2.493	63.3
10-3/4	V	-	-	0.802	20.4	2.518	64.0
11	V-1/2	23	-	0.81	20.6	2.543	64.6
11-1/4	W	-	25	0.818	20.8	2.569	65.2
11-1/2	W-1/2	24	-	0.826	21.0	2.594	65.9
11-3/4	X	-	-	0.834	21.2	2.619	66.5
12	X-1/2	25	27-1/2	0.842	21.4	2.644	67.2
12-1/4	Y	-	-	0.85	21.6	2.669	67.8
12-1/2	Z	26	28-3/4	0.858	21.8	2.694	68.4
12-3/4	Z-1/2	-	-	0.866	22.0	2.719	69.1
13	-	27	-	0.874	22.2	2.744	69.7
13-1/4	Z1	-	-	0.882	22.4	2.769	70.3
13-1/2	Z1-1/2	-	-	0.89	22.6	2.795	71.0
13-3/4	Z2	-	-	0.898	22.8	2.82	71.6
14	Z3	-	-	0.906	23.0	2.845	72.3
14-1/4	-	-	-	0.914	23.2	2.87	72.9
14-1/2	Z4	-	-	0.922	23.4	2.895	73.5
14-3/4	-	-	-	0.93	23.6	2.92	74.2
15	Z4-1/2	-	-	0.938	23.8	2.945	74.8
15-1/4	Z5	-	-	0.946	24.0	2.97	75.4
15-1/2	Z5-1/2	-	-	0.954	24.2	2.996	76.1
15-3/4	Z6	-	-	0.962	24.4	3.021	76.7
16	Z6-1/2	-	-	0.97	24.6	3.046	77.4
16-1/4	-			0.978	24.8	3.071	78.0
16-1/2	-			0.986	25.0	3.096	78.6
16-3/4	-			0.994	25.2	3.121	79.3
17	-			1.002	25.5	3.146	79.9
17-1/4	-			1.01	25.7	3.171	80.6
17-1/2	-			1.018	25.9	3.197	81.2
17-3/4	-			1.026	26.1	3.222	81.8
18	-			1.034	26.3	3.247	82.5
18-1/4	-			1.042	26.5	3.272	83.1
18-1/2	-			1.05	26.7	3.297	83.7
18-3/4	-			1.058	26.9	3.322	84.4
19	-			1.066	27.1	3.347	85.0
19-1/4	-			1.074	27.3	3.372	85.7
19-1/2	-			1.082	27.5	3.397	86.3
19-3/4	-			1.09	27.7	3.423	86.9
20	-			1.098	27.9	3.448	87.6
20-1/4	-			1.106	28.1	3.473	88.2
20-1/2	-			1.114	28.3	3.498	88.8
20-3/4	-			1.122	28.5	3.523	89.5
21	-			1.13	28.7	3.548	90.1
21-1/4	-			1.138	28.9	3.573	90.8
21-1/2	-			1.146	29.1	3.598	91.4
21-3/4	-			1.154	29.3	3.624	92.0
22	-			1.162	29.5	3.649	92.7
22-1/4	-			1.17	29.7	3.674	93.3
22-1/2	-			1.178	29.9	3.699	94.0
22-3/4	-			1.186	30.1	3.724	94.6
23	-			1.194	30.3	3.749	95.2
23-1/4	-			1.202	30.5	3.774	95.9
23-1/2	-			1.21	30.7	3.799	96.5
23-3/4	-			1.218	30.9	3.825	97.1
24	-			1.226	31.1	3.85	97.8
24-1/4	-			1.234	31.3	3.875	98.4
24-1/2	-			1.242	31.5	3.9	99.1
24-3/4	-			1.25	31.8	3.925	99.7
25	-			1.258	32.0	3.95	100.3
25-1/4	-			1.266	32.2	3.975	101.0
25-1/2	-			1.274	32.4	4.0	101.6
25-3/4	-			1.282	32.6	4.025	102.2
26	-			1.29	32.8	4.051	102.9
26-1/4				1.298	33.0	4.076	103.5