How do I measure my ring size at home?

Wrap string or soft tape at the finger base, mark the overlap, and measure in mm. Or measure an existing ring inner diameter. Full steps are in our how to measure ring size at home guide, and you can use the free printable ring sizer.

What is US size 10 ring in mm?

US size 10 is about 19.76 mm inside diameter and 62.1 mm circumference (UK T½, EU ≈62). See the size 10 row in the chart.

What is US size 11 ring in mm?

US size 11 is about 20.57 mm inside diameter and 64.6 mm circumference (UK V½, EU ≈65). Jump to size 11 in the table.

What is ring size 52 or 54 (EU)?

EU labels track inner circumference in mm. Size 52 is closest to ≈51.9–52.5 mm (about US 6–6¼ / UK L½–M). Size 54 is closest to ≈54.4 mm (about US 7 / UK N½).

What is the difference between US and UK ring sizes?

US uses numbers with quarter steps (6, 6.5, 7). UK uses letters (L, M, Q). Both map to the same mm diameter and circumference on this chart.

Ring Size Chart (US, UK, EU & mm)

Match inside diameter or circumference in millimeters to US numbers, UK letters, and EU sizes—then confirm with an at-home measurement.

How to measure at home · Printable ring sizer · Converter

Quick measure tips

Circumference (mm)

Wrap string or soft tape at the finger base
Mark the overlap and measure in mm
Find that value in Circumference (mm)

Diameter (mm)

Take a ring that fits the intended finger
Measure inner diameter with a ruler in mm
Match Diameter (mm) in the chart

Prefer a template? Use the printable ring size chart. Full walkthrough: measure ring size at home.

Soft tape wrapping a finger at the ring base to measure circumference in mm — Wrap at the ring base when fingers are warm—then match mm on the chart below.

Ring size conversion chart

US	UK	EU	Diameter (mm)	Circum. (mm)	Asia	India	Italy/Swiss	Dia. (in)	Circ. (in)
0	-	36.5	11.63	36.5	-	-	-	0.458	1.44
1/4	-	37.2	11.84	37.2	-	-	-	0.466	1.46
1/2	A	37.8	12.04	37.8	-	-	-	0.474	1.49
3/4	A+1/2	38.5	12.24	38.5	-	-	-	0.482	1.51
1	B	39.1	12.45	39.1	1	-	-	0.490	1.54
1+1/4	B+1/2	39.7	12.65	39.7	-	-	-	0.498	1.56
1+1/2	C	40.4	12.85	40.4	-	-	0.4	0.506	1.59
1+3/4	C+1/2	41	13.06	41.0	-	1	1	0.514	1.61
2	D	41.7	13.26	41.7	2	2	1.7	0.522	1.64
2+1/4	D+1/2	42.3	13.46	42.3	-	-	2.3	0.530	1.67
2+1/2	E	42.9	13.67	42.9	3	3	2.9	0.538	1.69
2+3/4	E+1/2	43.6	13.87	43.6	-	4	3.6	0.546	1.72
3	F	44.2	14.07	44.2	4	-	4.2	0.554	1.74
3+1/4	F+1/2	44.8	14.27	44.8	5	5	4.8	0.562	1.77
3+1/2	G	45.5	14.48	45.5	-	-	5.5	0.570	1.79
3+3/4	G+1/2	46.1	14.68	46.1	6	6	6.1	0.578	1.82
4	H	46.8	14.88	46.8	7	-	6.8	0.586	1.84
4+1/4	H+1/2	47.4	15.09	47.4	-	7	7.4	0.594	1.87
4+1/2	I	48	15.29	48.0	8	8	8	0.602	1.89
4+3/4	J	48.7	15.49	48.7	-	9	8.7	0.610	1.92
5	J+1/2	49.3	15.70	49.3	9	-	9.3	0.618	1.94
5+1/4	K	50	15.90	50.0	-	10	10	0.626	1.97
5+1/2	K+1/2	50.6	16.10	50.6	10	-	10.6	0.634	1.99
5+3/4	L	51.2	16.31	51.2	-	11	11.2	0.642	2.02
6	L+1/2	51.9	16.51	51.9	11	12	11.9	0.650	2.04
6+1/4	M	52.5	16.71	52.5	12	-	12.5	0.658	2.07
6+1/2	M+1/2	53.1	16.92	53.1	13	13	13.1	0.666	2.09
6+3/4	N	53.8	17.12	53.8	-	-	13.8	0.674	2.12
7	N+1/2	54.4	17.32	54.4	14	14	14.4	0.682	2.14
7+1/4	O	55.1	17.53	55.1	-	15	15.1	0.690	2.17
7+1/2	O+1/2	55.7	17.73	55.7	15	-	15.7	0.698	2.19
7+3/4	P	56.3	17.93	56.3	-	16	16.3	0.706	2.22
8	P+1/2	57	18.14	57.0	16	17	17	0.714	2.24
8+1/4	P+3/4	57.6	18.34	57.6	-	-	17.6	0.722	2.27
8+1/2	Q+1/4	58.3	18.54	58.3	17	18	18.3	0.730	2.29
8+3/4	R	58.9	18.75	58.9	-	19	18.9	0.738	2.32
9	R+1/2	59.5	18.95	59.5	18	-	19.5	0.746	2.34
9+1/4	S	60.2	19.15	60.2	-	20	20.2	0.754	2.37
9+1/2	S+1/2	60.8	19.35	60.8	19	21	20.8	0.762	2.39
9+3/4	T	61.4	19.56	61.4	-	-	21.4	0.770	2.42
10	T+1/2	62.1	19.76	62.1	20	22	22.1	0.778	2.44
10+1/4	U	62.7	19.96	62.7	21	23	22.7	0.786	2.47
10+1/2	U+1/2	63.4	20.17	63.4	22	-	23.4	0.794	2.49
10+3/4	V	64	20.37	64.0	-	24	24	0.802	2.52
11	V+1/2	64.6	20.57	64.6	23	25	24.6	0.810	2.54
11+1/4	W	65.3	20.78	65.3	-	-	25.3	0.818	2.57
11+1/2	W+1/2	65.9	20.98	65.9	24	26	25.9	0.826	2.59
11+3/4	X	66.6	21.18	66.6	-	-	26.6	0.834	2.62
12	X+1/2	67.2	21.39	67.2	25	27	27.2	0.842	2.65
12+1/4	Y	67.8	21.59	67.8	-	28	27.8	0.850	2.67
12+1/2	Y+1/2	68.5	21.79	68.5	26	-	28.5	0.858	2.70
12+3/4	Z	69.1	22.00	69.1	-	29	29.1	0.866	2.72
13	Z+1/2	69.7	22.20	69.7	27	30	29.7	0.874	2.75
13+1/4	Z1	70.4	22.40	70.4	-	-	30.4	0.882	2.77
13+1/2	-	71	22.61	71.0	-	31	31	0.890	2.80
13+3/4	Z2	71.7	22.81	71.7	-	32	31.7	0.898	2.82
14	Z3	72.3	23.01	72.3	-	-	32.3	0.906	2.85
14+1/4	-	72.9	23.22	72.9	-	33	32.9	0.914	2.87
14+1/2	Z4	73.6	23.42	73.6	-	-	33.6	0.922	2.90
14+3/4	-	74.2	23.62	74.2	-	34	34.2	0.930	2.92
15	-	74.8	23.83	74.8	-	35	34.8	0.938	2.95
15+1/4	-	75.5	24.03	75.5	-	-	35.5	0.946	2.97
15+1/2	-	76.1	24.23	76.1	-	36	36.1	0.954	3.00
15+3/4	-	76.8	24.43	76.8	-	-	36.8	0.962	3.02
16	-	77.4	24.64	77.4	-	37	37.4	0.970	3.05

US vs UK vs EU (quick guide)

United States

Numerical sizes with quarter steps (e.g. 6, 6.5, 10).

United Kingdom

Alphabetical sizes (e.g. L, M, Q) with half letters—same mm as US rows.

Europe (EU)

Labels follow inner circumference in mm (e.g. ~52, ~54). Use the EU column or Circum. (mm).

Ring size chart FAQ

Ring chart sources

Rows map inside diameter and circumference in mm to US numbers, UK letters, and EU circumference labels. Jewelers can still round differently—confirm with a physical sizer.

ISO 8653 jewellery — ring-sizes
Standard / specification · Last checked: 2026-10-05
https://www.iso.org/standard/44534.html
SizeFit how to measure ring size
Secondary source · Last checked: 2026-10-05
https://sizefit.org/guides/how-to-measure-ring-size

Full method: How we source size data

Ring Size Chart (US, UK, EU & mm)

Circumference (mm)

Diameter (mm)

United States

United Kingdom

Europe (EU)

Ring size chart FAQ

Related tools & guides

Measure at home

Printable ring sizer

Ring size converter

Men's ring size chart