Ring Size Converter

Convert ring sizes between US, UK, EU, and Japanese sizing systems. Whether you are buying an engagement ring, a wedding band, or any other ring from an international retailer, enter your size below for an instant conversion.

Type a size to convert

Ring Size Chart

US	UK	EU	JP	Inner circumference
3	F	44	4	44.2mm
3.5	G	45.5	5	45.5mm
4	H	47	7	46.8mm
4.5	I	48	8	48mm
5	J	49	9	49.3mm
5.5	K	50.5	10	50.6mm
6	L	51.5	12	51.9mm
6.5	M	53	13	53.1mm
7	N	54	14	54.4mm
7.5	O	55.5	15	55.7mm
8	P	57	16	57mm
8.5	Q	58	17	58.3mm
9	R	59	18	59.5mm
9.5	S	60.5	19	60.8mm
10	T	62	20	62.1mm
10.5	U	63	22	63.4mm
11	V	64	23	64.6mm
11.5	W	65.5	24	65.9mm
12	X	67	25	67.2mm
13	Z	69.5	27	69.7mm

How to Measure Your Ring Size

String Method

Wrap a piece of string or a thin strip of paper around the base of your finger. Mark where it overlaps, then measure the length in millimetres. Match this circumference measurement to the chart above to find your size.

Existing Ring Method

Place a ring that fits well on a ruler and measure the inner diameter in millimetres. Multiply by 3.14159 to get the circumference, then look up the result in the size chart. This method works best with a ring that fits the intended finger.

Consider Width

Wider bands (6 mm and above) fit more snugly than thinner bands. If you are buying a wide ring, consider going up half a size for a comfortable fit that slides over the knuckle easily.

Temperature Matters

Your fingers change size with temperature. Measure when your hands are at a normal temperature, ideally in the late afternoon. Avoid measuring right after exercise, or when your hands are very cold or very hot.

Frequently Asked Questions

How do I find my ring size at home?

Wrap a thin strip of paper or string snugly around the base of your finger. Mark where the ends overlap, then measure the length in millimetres. This gives you the inner circumference. Use our size chart to find the corresponding ring size in your preferred system.

What is a US ring size 7 in UK and EU?

A US ring size 7 is equivalent to a UK size N and an EU size 54. In the Japanese system, it corresponds to size 14. These conversions are based on an inner circumference of approximately 54.4 mm.

Does the UK use letters for ring sizes?

Yes, the UK ring sizing system uses letters from A through Z, with each half-size represented by a separate letter. For example, size J is roughly US 5, size N is US 7, and size T is US 10. This alphabetical system is also used in Australia, Ireland, and New Zealand.

Should I measure my ring size in the morning or evening?

Fingers tend to swell throughout the day and in warm weather. For the most accurate result, measure in the late afternoon or evening when your fingers are at their largest. Avoid measuring when your hands are cold, as this can give a smaller reading.