Ring size converter
Finger Circumference to Ring Size
Measure the circumference (not diameter) of your finger with a strip of paper or soft tape.
· diameter = circumference ÷ π
Full size chart
| Circumference (cm) | Diameter (mm) | US size | UK size | EU size |
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Frequently asked
How do I measure my finger circumference at home?
Wrap a thin strip of paper or a piece of string snugly around the base of the finger you want to size. Mark where it overlaps, then lay it flat against a ruler. That length in centimeters is your finger circumference — enter it above.
Should I measure in the morning or evening?
Fingers swell slightly throughout the day, especially in heat or after exercise. For the most comfortable fit, measure in the afternoon when your fingers are at their typical size. Avoid measuring when you’re cold — fingers shrink and the ring may be loose later.
What if my size falls between two sizes?
Always round up to the larger size. A ring that’s slightly loose is easier to resize or use a ring adjuster on than one that’s too tight to get off comfortably.
Are US and Canadian ring sizes the same?
Yes — Canada uses the same numerical ring sizing system as the United States. UK and Australian sizes use letters, while most of continental Europe uses a numerical EU system based on the inner circumference in millimeters.
What is the most common women’s ring size?
For women, the most common ring size is US 6 to 7 (approximately 5.2–5.7 cm circumference). For men, the average falls between US 9 and 10 (approximately 6.1–6.5 cm circumference).