Ring size converter
Pick the system you know your size in, type it, and read the same size in every other system.
Use this ring size converter when you know your size in one country and need it in another. The same ring has a different name in each place: a US 7 is an N½ in the UK and a 54 in Europe. Look up the size you know, and you will know what to ask for when you buy a ring abroad or online. All the matches here come from the conversion table on Wikipedia's ring size page.
Turning a UK ring size into a US one
In the UK a ring size is a letter, and in the US it is a number. Both have in-between sizes too: N½ means "N and a half", a size between N and O. UK N½ is the same ring as US 7, and UK S½ is the same ring as US 9½. Ireland and Australia use the UK letters, and Canada and Mexico use the US numbers.
Each UK letter is one small step bigger than the letter before it, and the US steps are a little different. So a few letters have no exact US match, and the chart gives the closest one.
How do I turn a US ring size into a UK one?
Find your US number in the chart, then look next to it for the letter. US 6 is UK L½, US 8 is UK P½, and US 10 is UK T½. Many US sizes match a UK half size like these, so don't worry if your letter has a ½.
A UK to US chart for common letters
The last column is the length all the way round the inside of the ring, in millimetres (mm).
| UK | US | Around the inside (mm) |
|---|---|---|
| J½ | 5 | 49.3 |
| K | 5¼ | 50.0 |
| L½ | 6 | 51.9 |
| M½ | 6½ | 53.1 |
| N | 6¾ | 53.8 |
| N½ | 7 | 54.4 |
| P½ | 8 | 57.0 |
| R½ | 9 | 59.5 |
| T½ | 10 | 62.1 |
| U½ | 10½ | 63.4 |
| V½ | 11 | 64.6 |
UK ring sizes measured in mm
A ring can be measured straight across the inside, which is called the diameter, or all the way round the inside, which is called the circumference. UK sizes follow the length round the inside: UK N½, for example, is about 54 mm round.
In Europe, the size is that same length round the inside, in whole millimetres, as the European ring size standard sets out. So a UK N½, at about 54 mm round, is simply a European 54.
How big is a US ring size in millimetres?
Each whole US size is a little under 1 mm wider than the one before. A US 7, for example, is about 17 mm across the inside and 54 mm round. A US 5 is nearly 16 mm across, and a US 10 is nearly 20 mm. Type any size into the converter to get its exact millimetres.
Which ring size fits 2 inches?
If a paper strip round your finger measures 2 inches, your size is about a US 5½, which is K½ in UK letters.
Questions people often ask
Can I measure my ring size with my phone?
Yes, with the ring size tool on this site's home page. First hold a bank card against the card shown on your screen, and slide the bar until the two are the same size. That lets the tool draw its circles at their real size. Then lay a ring on the circle, or type the length of your paper strip, and your size appears for every country.
Does a ring size chart work in centimetres?
Yes. If your ruler is in centimetres, a strip of 5.4 cm is the same as 54 mm, which is a European 54 and about a US 7.
Why do Japanese and Indian sizes sometimes appear as a range?
Japan and India have no half sizes, and their sizes don't step up quite like US sizes. So when a US size falls between two of theirs, the chart shows both, like "13 to 14". The standard table lists Japanese sizes up to 27, which is a US 13; for bigger rings, ask the shop for its own chart.