Mens Ring Size Chart

Men’s ring sizes run from about US 8 to 15 (UK P½ to Z+, EU 57 to 75), with US 9 to 10 the most common. Each row below gives the inner diameter and circumference in mm with the UK, EU and Japanese equivalents; type a measurement into the finder to see where a ring or finger sits. US 10 is 19.76 mm across.

The size

US 10

UK U · EU 62 · Japan 21

An inner diameter of 19.8 mm is a circumference of 62.2 mm. That is almost exactly a US 10.

US / Canada 10 (exact)
UK / Australia U (exact)
EU / ISO 62 (exact)
Japan 21 (+0.4 mm)
Inner diameter 19.8 mm (0.78 in)
Inner circumference 62.2 mm (2.45 in)

US	Diameter mm	Circumference mm	UK	EU / ISO	Japan
3	14.07	44.2	F½	44	4
3½	14.47	45.5	G½	45.5	5
4	14.88	46.8	H½	47	7
4½	15.29	48	I½	48	8
5	15.69	49.3	J½	49.5	9
5½	16.1	50.6	K½	50.5	10
6	16.51	51.9	L½	52	12
6½	16.91	53.1	M½	53	13
7	17.32	54.4	N½	54.5	14
7½	17.73	55.7	O½	55.5	15
8	18.13	57	P½	57	16
8½	18.54	58.2	Q½	58	18
9	18.95	59.5	R½	59.5	19
9½	19.35	60.8	S½	61	20
10 ◀	19.76	62.1	T½	62	21
10½	20.16	63.3	U½	63.5	22
11	20.57	64.6	V½	64.5	24
11½	20.98	65.9	W½	66	25
12	21.38	67.2	X½	67	26
12½	21.79	68.5	Z	68.5	27
13	22.2	69.7	Z+1	69.5	29
13½	22.6	71	Z+2	71	30
14	23.01	72.3	Z+3	72.5	31
14½	23.42	73.6	Z+4	73.5	32
15	23.82	74.8	Z+5	75	33

How is the men’s chart worked out?

The same scales as any ring: US diameter = 11.63 + 0.8128 × size; circumference = π × diameter; UK = 37.5 + 1.25 × letter; EU = circumference; Japan diameter = 13 + (size − 1) ÷ 3.

Worked example. US 10: 11.63 + 0.8128 × 10 = 19.76 mm across; π × 19.76 = 62.1 mm around. UK: (62.07 − 37.5) ÷ 1.25 = 19.66, nearest letter T½. EU 62. Japan: (19.76 − 13) × 3 + 1 = 21.3, nearest 21.

The men’s range in every scale

US 8 to 15 with mm, UK, EU and Japan
US	Diameter mm	Around mm	UK	EU	Japan
8	18.13	57	P½	57	16
8½	18.54	58.2	Q½	58	18
9	18.95	59.5	R½	59.5	19
9½	19.35	60.8	S½	61	20
10	19.76	62.1	T½	62	21
10½	20.16	63.3	U½	63.5	22
11	20.57	64.6	V½	64.5	24
11½	20.98	65.9	W½	66	25
12	21.38	67.2	X½	67	26
12½	21.79	68.5	Z	68.5	27
13	22.2	69.7	Z+1	69.5	29
13½	22.6	71	Z+2	71	30
14	23.01	72.3	Z+3	72.5	31
14½	23.42	73.6	Z+4	73.5	32
15	23.82	74.8	Z+5	75	33

Width changes the fit

Most men’s bands are 5 to 8 mm wide. A wide band presses on more skin and cannot tilt, so it feels tighter than a thin band of the same inner size; the usual advice is a quarter size up at 6 mm and a half size up at 8 mm. Comfort-fit bands, rounded on the inside, feel looser than flat ones and often go a quarter size down.

Sizes that are hard to find

Above US 13 many ready-made rings are special orders, and the converter matters more because the scales drift apart at the top: US 14 is 72.3 mm around, which EU labels 72.5 and the UK scale labels Z+3.

Questions about men’s ring sizes

What is the average men’s ring size?

US 9 to 10, by what jewellers sell, with most men between 8 and 12. US 10 is 19.76 mm across and 62.1 mm around.

Do men’s rings use a different scale?

No. The same scales cover everyone; men’s sizes are simply the upper part of each. This chart starts at US 8 (UK P½, EU 57) because almost no men’s ring is smaller, and runs to US 15.

Do wide bands need a bigger size?

Yes. A band 6 to 8 mm wide covers more of the finger and feels tighter than a thin band of the same size, so jewellers advise a quarter to a half size up for wide bands, which most men’s rings are.

How do I measure a man’s finger without him knowing?

Borrow a ring he wears on that finger and lay it on the on-screen sizer or measure its inside with a ruler; or press it into soap and measure the mark. If he has no ring, the string method on the measuring page takes thirty seconds while he is asleep, if you are brave.

What about the knuckle?

Men’s knuckles are often a size larger than the base of the finger. Measure both and pick between them: the ring must go over the knuckle, and a slightly loose ring at the base is normal for that reason.