Ring size chart & converter
Enter a ring size in any of the four systems below, or the inside circumference in millimetres if you've measured an existing ring, and the other three sizes are calculated instantly.
Result
- US / Canada
- 7
- UK / AU / IE
- N½
- EU / FR / DE
- 54
- Japan
- 14
- Circumference
- 54.4 mm
- Diameter
- 17.3 mm
The four scales in this converter are all measuring the same physical thing — the inside circumference of the ring — just labelled differently. US/Canada and UK/Australia/Ireland use their own numbered or lettered scales; most of continental Europe sizes rings by the circumference in millimetres directly; Japan uses its own numbered scale that tracks circumference closely but not identically to the EU one.
If you already own a ring that fits well, measuring it directly (lay a piece of string around the inside, mark the overlap, measure the length) is more accurate than any finger-measuring method, because it isn’t affected by knuckle size, temperature or time of day.
United Kingdom
UK sizing sits between the two systems most UK shoppers actually order from: US retailers (Amazon.com, US-only brands) and EU ones (Zalando, ASOS' EU warehouses since Brexit changed cross-border returns). A UK 6 shoe, a UK M ring and a UK 34C bra are each a different number again once the label says US or EU — which is why three-way conversion gets searched here more than in most single-market countries.
Every conversion on this page runs in your browser. Nothing you type is uploaded anywhere.
Frequently asked questions
How do I measure my ring size at home?
Wrap a strip of paper or string around the base of the finger, mark where it overlaps, then measure that length in millimetres — that's the circumference to enter above. Measuring an existing ring that already fits is more reliable than measuring a finger directly, since fingers change size slightly through the day.
Why do two rings with the "same" size fit differently?
Band width and shape both affect fit at a given circumference — a wide flat band feels tighter than a thin round one at the same nominal size, and this chart gives the industry-standard figure, not a guarantee for every design.
Is there a universal ring size standard?
No single global standard — US/Canada, UK/Australia/Ireland, most of continental Europe, and Japan each use their own scale, which is exactly why a converter is useful rather than a single chart.
Last updated: 2026-09-10