Ring Size Chart & Ring Size Converter

Find your ring size in US, UK, European, Middle Eastern, Japanese, Indian and other international sizes. A ring size is set by the inside circumference or diameter of the ring: a US size 7 is 17.3 mm across the inside and 54.4 mm around, which is UK N½, European size 54.4, Japanese 14 and Indian 14.

Updated October 2026 · Grown Leo

Ring size converter

Pick the country system you know, then your size. US is selected by default.

Size system Size

Ring size calculator

Enter your finger circumference or the inside diameter of a ring that fits.

I measured Value

Your size in every system will appear here.

International ring size chart

Ring size conversion chart: US sizes and their international equivalents
US & Canada	UK & Australia	Europe & Middle East	Japan, China, Korea	India	Italy, Spain, Switzerland	Germany, Netherlands	Russia	Diameter (mm)	Circumference (mm)
3	F	44.2	4	5	4.2	14.1	14	14.1	44.2
3½	G	45.5	6	6	5.5	14.5	14.5	14.5	45.5
4	H	46.8	7	7	6.8	14.9	15	14.9	46.8
4½	I	48.0	8	8	8.0	15.3	15.5	15.3	48.0
5	J½	49.3	9	10	9.3	15.7	15.5	15.7	49.3
5½	K½	50.6	10	11	10.6	16.1	16	16.1	50.6
6	L½	51.9	11	12	11.9	16.5	16.5	16.5	51.9
6½	M½	53.1	13	13	13.1	16.9	17	16.9	53.1
7	N½	54.4	14	14	14.4	17.3	17.5	17.3	54.4
7½	O½	55.7	15	16	15.7	17.7	17.5	17.7	55.7
8	P½	57.0	16	17	17.0	18.1	18	18.1	57.0
8½	Q¼	58.3	17	18	18.3	18.5	18.5	18.5	58.3
9	R½	59.5	18	20	19.5	18.9	19	18.9	59.5
9½	S½	60.8	19	21	20.8	19.4	19.5	19.4	60.8
10	T½	62.1	20	22	22.1	19.8	20	19.8	62.1
10½	U½	63.4	22	24	23.4	20.2	20	20.2	63.4
11	V½	64.6	23	25	24.6	20.6	20.5	20.6	64.6
11½	W½	65.9	24	26	25.9	21.0	21	21.0	65.9
12	X½	67.2	25	27	27.2	21.4	21.5	21.4	67.2
12½	Y½	68.5	26	29	28.5	21.8	22	21.8	68.5
13	Z½	69.7	27	30	29.7	22.2	22	22.2	69.7

Japanese and Indian sizes don't follow a fixed step, so where a US size has no exact match the closest equivalent is shown. Grown Leo rings are offered in US sizes 4 to 12.

How to measure your ring size at home

Measure your finger: wrap a strip of paper or a piece of string around the base of the finger, mark where it overlaps and measure the length in millimeters. That is your finger circumference.
Measure a ring that fits: place it on a ruler and measure the inside diameter, edge to edge, in millimeters.
Convert it: enter the number in the ring size calculator above, or find the closest value in the international ring size chart.

Measure at the end of the day when your fingers are at their largest, avoid measuring when your hands are cold, and make sure the size still slides over your knuckle.

How ring size systems work around the world

US, Canada and Mexico: numbers in quarter sizes. Each whole size adds 0.032 inches (0.81 mm) to the inside diameter. The formula is: circumference in mm = 2.55 × US size + 36.5.
UK, Ireland, Australia, New Zealand and South Africa: letters from A to Z with half sizes. Each half letter adds about 1.25 mm to the circumference.
Europe and the Middle East (ISO 8653): the size is the inside circumference in millimeters, for example 54. Used across continental Europe, including France, Austria, Belgium and the Nordic countries, and in Gulf countries such as the UAE and Saudi Arabia.
Japan, China, South Korea and South America: whole numbers that do not follow a fixed millimeter step.
India: whole numbers, from about 1 to 35, that also do not follow a fixed step.
Italy, Spain and Switzerland: the inside circumference minus 40 mm, so size 14 is 54 mm.
Germany and the Netherlands: the inside diameter in millimeters, for example 17.3.
Russia: the inside diameter rounded to the nearest half millimeter, for example 17.5.

European & Middle East ring size to US

Gulf and European sizes are the inside circumference in mm. Size 54 is US 6¾ and size 57 is US 8.

Europe & Middle East size (mm)	US size
44	3
45	3¼
46	3¾
47	4
48	4½
49	4¾
50	5¼
51	5¾
52	6
53	6½
54	6¾
55	7¼
56	7½
57	8
58	8½
59	8¾
60	9¼
61	9½
62	10
63	10¼
64	10¾
65	11¼
66	11½
67	12
68	12¼
69	12¾
70	13

UK ring size to US

UK sizes are letters; about two letters make one US size. UK N½ is US 7.

UK size	US size
F	3
F½	3¼
G	3½
G½	3¾
H	4
H½	4¼
I	4½
J	4¾
J½	5
K	5¼
K½	5½
L	5¾
L½	6
M	6¼
M½	6½
N	6¾
N½	7
O	7¼
O½	7½
P	7¾
P½	8
P¾	8¼
Q¼	8½
R	8¾
R½	9
S	9¼
S½	9½
T	9¾
T½	10
U	10¼
U½	10½
V	10¾
V½	11
W	11¼
W½	11½
X	11¾
X½	12
Y	12¼
Y½	12½
Z	12¾
Z½	13

Japanese ring size to US

Japanese size 14 is US 7. Between US 5 and 10 the Japanese size is roughly double the US size.

Japanese size	US size
1	1
2	2
3	2½
4	3
5	3¼
6	3¾
7	4
8	4½
9	5
10	5½
11	6
12	6¼
13	6½
14	7
15	7½
16	8
17	8½
18	9
19	9½
20	10
21	10¼
22	10½
23	11
24	11½
25	12
26	12½
27	13

Indian ring size to US

Indian size 14 is US 7 and size 22 is US 10.

Indian size	US size
1	1¾
2	2
3	2½
4	2¾
5	3¼
6	3¾
7	4¼
8	4½
9	4¾
10	5¼
11	5¾
12	6
13	6½
14	7
15	7¼
16	7¾
17	8
18	8½
19	8¾
20	9¼
21	9½
22	10
23	10¼
24	10¾
25	11
26	11½
27	12
28	12¼
29	12¾
30	13
31	13½
32	13¾

Tips for choosing the right ring size

If you are between two sizes, choose the larger one.
Wide bands fit more snugly than thin bands, so go up half a size for a wide band.
Fingers swell in heat and shrink in the cold; measure at room temperature.
Buying a surprise ring? Measure the inside diameter of a ring they already wear on the same finger.

Ready to choose? Browse our moissanite engagement rings and lab grown diamond engagement rings, offered in US sizes 4 to 12. For a full walkthrough, read our ring size chart guide. Choosing a stone? See how big each carat looks with our diamond size chart.

Ring size FAQs

What is a size 54 ring in US sizes?

A size 54 ring is a European or Middle Eastern size, which means the inside circumference is 54 mm. That converts to US size 6¾. A US size 7 measures 54.4 mm around.

How do I convert a UK ring size to a US ring size?

UK ring sizes use letters and US sizes use numbers. Each US whole size is about two UK letters, so UK N½ is US 7, UK P½ is US 8 and UK L½ is US 6. Use the converter above to check any letter.

What is a Japanese ring size in US sizes?

Japanese ring sizes are whole numbers. Japanese size 14 is US 7, size 11 is US 6 and size 20 is US 10. Between US 5 and US 10 a Japanese size is roughly double the US size.

What is an Indian ring size in US sizes?

Indian ring sizes are whole numbers from 1 to about 35. Indian size 14 is US 7, size 12 is US 6 and size 22 is US 10.

Which ring size system is used in the Middle East?

The UAE, Saudi Arabia and other Gulf countries generally use the same system as Europe: the ring size is the inside circumference in millimeters, so a size 54 ring is 54 mm around and equals US 6¾.

How do I convert ring size from millimeters to US size?

Measure the inside circumference in millimeters, subtract 36.5 and divide by 2.55. For example, 54.4 mm gives US size 7. If you measured the inside diameter instead, multiply it by 3.1416 first to get the circumference.

How can I measure my ring size at home?

Wrap a strip of paper or string around the base of your finger, mark where it overlaps and measure the length in millimeters. Enter that number in the ring size calculator above to see your size in every system.

Are men's and women's ring sizes different?

No. Men's and women's rings use the same size scales. Men usually wear larger sizes, but a US size 9 is the same for everyone.

What should I do if I am between two ring sizes?

Choose the larger size. Fingers swell in warm weather and later in the day, and a ring that is slightly loose is more comfortable than one that will not pass the knuckle. Go up half a size for wide bands.

What ring sizes does Grown Leo offer?

Grown Leo rings are offered in US sizes 4 to 12, including half sizes. Contact us if you need a size outside this range.