Ring Size Converter
Find your ring size across different international standards.
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How Ring Size Conversion Works
A ring size describes the inner diameter (or circumference) of the band. Different countries label the same physical size differently — the US uses numbers, the UK uses letters, and the EU and Japan use the circumference in millimeters. Our converter uses the inner diameter as the common reference.
Example
A US 7 ring has an inner diameter of about 17.3 mm and converts to UK N, EU 54 and Japan 14.
How to Measure Your Ring Size
- Wrap a strip of paper around the base of your finger and mark where it overlaps — that length is the circumference.
- Or measure the inner diameter of a ring that already fits.
- Measure when your hands are warm; fingers shrink in the cold.
Frequently Asked Questions
Wrap a strip of paper around your finger and measure the length where it overlaps (the circumference), or measure the inner diameter of a ring that fits, then enter it in the converter.
The US uses a numeric scale while the UK uses letters. A US 7 is equivalent to a UK N. Both describe the same inner diameter.
Yes. Fingers can shrink in cold weather and swell in heat or late in the day. Measure when your hands are at a normal, warm temperature for the most reliable size.
Embed this tool on your website
Free to use — copy this code onto your site. It stays up to date automatically and includes a link back to CalcSun.