Ring size chart

Every quarter size from US 3 to US 14, in all seven systems, with inner diameter and circumference in millimetres and inches.

Every value is computed from the published standard — nothing is copied from another chart, and nothing is behind a download. The site currently ranking first for this search publishes its chart as an image, so none of it can be read, copied or searched.

Don’t know your size yet? The ring sizer measures it against your screen in about a minute.

Every size, every system

US sizes are sold in quarters, so the chart is built in quarters. India, France, Italy, Spain and Brazil share one scale — inner circumference in millimetres minus 40 — which is why those columns agree.

Ring size conversion chart in quarter sizes: US and Canada, UK and Australia, EU/ISO, Japan, India, France/Italy/Spain, Brazil, with inner diameter and circumference in millimetres and inches.
US / CA	UK / AU	EU / ISO	Japan	India	FR / IT / ES	Brazil	Diameter	Ø inches	Circumference	Circ. inches
3	F½	44	4	4	4	4	14.07 mm	0.554	44.21 mm	1.740
3¼	G	45	5	5	5	5	14.27 mm	0.562	44.85 mm	1.766
3½	G½	45	5	5	5	5	14.48 mm	0.570	45.48 mm	1.791
3¾	H	46	6	6	6	6	14.68 mm	0.578	46.12 mm	1.816
4	H½	47	7	7	7	7	14.88 mm	0.586	46.76 mm	1.841
4¼	I	47	7	7	7	7	15.09 mm	0.594	47.40 mm	1.866
4½	I½	48	8	8	8	8	15.29 mm	0.602	48.04 mm	1.891
4¾	J	49	8	9	9	9	15.49 mm	0.610	48.68 mm	1.916
5	J½	49	9	9	9	9	15.70 mm	0.618	49.31 mm	1.942
5¼	K	50	10	10	10	10	15.90 mm	0.626	49.95 mm	1.967
5½	K½	51	10	11	11	11	16.10 mm	0.634	50.59 mm	1.992
5¾	L	51	11	11	11	11	16.31 mm	0.642	51.23 mm	2.017
6	L½	52	12	12	12	12	16.51 mm	0.650	51.87 mm	2.042
6¼	M	53	12	13	13	13	16.71 mm	0.658	52.51 mm	2.067
6½	M½	53	13	13	13	13	16.92 mm	0.666	53.14 mm	2.092
6¾	N	54	13	14	14	14	17.12 mm	0.674	53.78 mm	2.117
7	N½	54	14	14	14	14	17.32 mm	0.682	54.42 mm	2.143
7¼	O	55	15	15	15	15	17.53 mm	0.690	55.06 mm	2.168
7½	O½	56	15	16	16	16	17.73 mm	0.698	55.70 mm	2.193
7¾	P	56	16	16	16	16	17.93 mm	0.706	56.34 mm	2.218
8	P½	57	16	17	17	17	18.14 mm	0.714	56.97 mm	2.243
8¼	Q	58	17	18	18	18	18.34 mm	0.722	57.61 mm	2.268
8½	Q½	58	18	18	18	18	18.54 mm	0.730	58.25 mm	2.293
8¾	R	59	18	19	19	19	18.75 mm	0.738	58.89 mm	2.318
9	R½	60	19	20	20	20	18.95 mm	0.746	59.53 mm	2.344
9¼	S	60	19	20	20	20	19.15 mm	0.754	60.17 mm	2.369
9½	S½	61	20	21	21	21	19.35 mm	0.762	60.80 mm	2.394
9¾	T	61	21	21	21	21	19.56 mm	0.770	61.44 mm	2.419
10	T½	62	21	22	22	22	19.76 mm	0.778	62.08 mm	2.444
10¼	U	63	22	23	23	23	19.96 mm	0.786	62.72 mm	2.469
10½	U½	63	23	23	23	23	20.17 mm	0.794	63.36 mm	2.494
10¾	V	64	23	24	24	24	20.37 mm	0.802	64.00 mm	2.520
11	V½	65	24	25	25	25	20.57 mm	0.810	64.64 mm	2.545
11¼	W	65	24	25	25	25	20.78 mm	0.818	65.27 mm	2.570
11½	W½	66	25	26	26	26	20.98 mm	0.826	65.91 mm	2.595
11¾	X	67	26	27	27	27	21.18 mm	0.834	66.55 mm	2.620
12	Y	67	26	27	27	27	21.39 mm	0.842	67.19 mm	2.645
12¼	Y½	68	27	28	28	28	21.59 mm	0.850	67.83 mm	2.670
12½	Z	68	27	28	28	28	21.79 mm	0.858	68.47 mm	2.695
12¾	Z½	69	28	29	29	29	22.00 mm	0.866	69.10 mm	2.721
13	Z+1	70	29	30	30	30	22.20 mm	0.874	69.74 mm	2.746
13¼	Z+1½	70	29	30	30	30	22.40 mm	0.882	70.38 mm	2.771
13½	Z+2	71	30	31	31	31	22.61 mm	0.890	71.02 mm	2.796
13¾	Z+2½	72	30	32	32	32	22.81 mm	0.898	71.66 mm	2.821
14	Z+3	72	31	32	32	32	23.01 mm	0.906	72.30 mm	2.846

UK sizes run as long stretches of half letters. That is correct, not a bug: a US quarter step is 0.64 mm of circumference and a UK half letter is 0.625 mm, so the two scales drift against each other and never line up. Why charts disagree

Women’s ring size chart

The range jewellers actually stock for women, US 3 to 9. The commonest is US 6. There is no census of finger sizes — these figures describe what sells, so treat them as a sanity check, not a verdict.

Women’s ring sizes, US 3 to 9, in every system
US / CA	UK / AU	EU / ISO	Japan	India	Diameter
3	F½	44	4	4	14.07 mm
3¼	G	45	5	5	14.27 mm
3½	G½	45	5	5	14.48 mm
3¾	H	46	6	6	14.68 mm
4	H½	47	7	7	14.88 mm
4¼	I	47	7	7	15.09 mm
4½	I½	48	8	8	15.29 mm
4¾	J	49	8	9	15.49 mm
5	J½	49	9	9	15.70 mm
5¼	K	50	10	10	15.90 mm
5½	K½	51	10	11	16.10 mm
5¾	L	51	11	11	16.31 mm
6most common	L½	52	12	12	16.51 mm
6¼	M	53	12	13	16.71 mm
6½	M½	53	13	13	16.92 mm
6¾	N	54	13	14	17.12 mm
7	N½	54	14	14	17.32 mm
7¼	O	55	15	15	17.53 mm
7½	O½	56	15	16	17.73 mm
7¾	P	56	16	16	17.93 mm
8	P½	57	16	17	18.14 mm
8¼	Q	58	17	18	18.34 mm
8½	Q½	58	18	18	18.54 mm
8¾	R	59	18	19	18.75 mm
9	R½	60	19	20	18.95 mm

Men’s ring size chart

US 8 to 14, with US 9 the commonest. The same caveat applies: this is what jewellers sell, not a measurement of the population.

Men’s ring sizes, US 8 to 14, in every system
US / CA	UK / AU	EU / ISO	Japan	India	Diameter
8	P½	57	16	17	18.14 mm
8¼	Q	58	17	18	18.34 mm
8½	Q½	58	18	18	18.54 mm
8¾	R	59	18	19	18.75 mm
9most common	R½	60	19	20	18.95 mm
9¼	S	60	19	20	19.15 mm
9½	S½	61	20	21	19.35 mm
9¾	T	61	21	21	19.56 mm
10	T½	62	21	22	19.76 mm
10¼	U	63	22	23	19.96 mm
10½	U½	63	23	23	20.17 mm
10¾	V	64	23	24	20.37 mm
11	V½	65	24	25	20.57 mm
11¼	W	65	24	25	20.78 mm
11½	W½	66	25	26	20.98 mm
11¾	X	67	26	27	21.18 mm
12	Y	67	26	27	21.39 mm
12¼	Y½	68	27	28	21.59 mm
12½	Z	68	27	28	21.79 mm
12¾	Z½	69	28	29	22.00 mm
13	Z+1	70	29	30	22.20 mm
13¼	Z+1½	70	29	30	22.40 mm
13½	Z+2	71	30	31	22.61 mm
13¾	Z+2½	72	30	32	22.81 mm
14	Z+3	72	31	32	23.01 mm

Millimetres, centimetres and inches

These are the same measurement written three ways, so no conversion table is needed — divide millimetres by 10 for centimetres, or by 25.4 for inches. What matters far more is which measurement you have.

Inner diameter: Straight across the inside of the ring, edge to edge. This is the number every size system is built from, and the one to give a jeweller. US 6 is 16.51 mm.
Inner circumference: All the way round the inside — what a paper strip round your finger measures. It is exactly π × the diameter, which is why EU/ISO sizes are this number. US 6 is 51.87 mm.

Mixing the two up is the commonest sizing mistake there is, and it puts you out by roughly three times — a 16 mm circumference is a child’s ring; a 16 mm diameter is about US 5½.

Where these numbers come from

The standard behind each sizing system
System	Standard	Rule
EU / ISO	ISO 8653:2016	Size = inner circumference in mm
UK / AU	BS EN 28653:1993	C = 40 mm, +1.25 mm per letter
Japan	JIS S 4700:2022	Size 1 = 13 mm diameter, +⅓ mm per size
Brazil	ABNT NBR 16058	Size = circumference − 40 (aligned to ISO 8653)
FR / IT / ES	—	Size = circumference − 40
US / CA	No governing standard	Size 0 = 0.458 in, +0.032 in per size
India	No standard exists	Circumference − 40, per four jewellers’ published charts

Two systems have no standard behind them, and we say so rather than presenting a number as settled. India has no BIS specification; Tanishq’s own chart runs about a size smaller than the convention four other Indian jewellers publish. UK letter charts vary by up to half a size depending on which half letters a given scale includes.

The full working — including where four ranking sites give three different UK answers for the same ring — is on the ring sizer page.