Ring Size Converter: Korean, US, UK, EU, Japan
Ring sizes don't line up across countries — a Korean size 13 is roughly US 6.5, UK M, EU 53. This converter handles the major systems and explains how to measure your finger accurately.
Most ring size systems use the inner circumference (or diameter) of the ring. Korea uses a sequential number scale; the US a half-sized scale; Europe uses circumference in mm; Japan uses its own number scale. The conversion is mathematical — match by inner circumference.
Common ring size conversions
| Korean | US | UK | EU (mm) | Japan |
|---|---|---|---|---|
| 10 | 5 | J½ | 49 | 9 |
| 12 | 6 | L½ | 52 | 12 |
| 14 | 7 | N½ | 54 | 14 |
| 16 | 8 | P½ | 57 | 16 |
| 18 | 9 | R½ | 59 | 18 |
| 20 | 10 | T½ | 62 | 20 |
How to measure ring size at home
- •Wrap a thin strip of paper around your finger; mark where it meets
- •Measure the marked length in mm — that's your inner circumference
- •Convert via the table or this calculator
- •Measure at the end of the day; fingers swell with heat and humidity
- •Account for knuckle size — the ring needs to slide over it
Extended FAQ
Are men's and women's ring sizes different?
Same scale; men's fingers are typically larger so men's rings are larger by number. Don't confuse a 'women's size 7' with a 'men's size 7' — they're the same physical ring.
Are my measurements stored?
No — runs entirely in your browser.