Jewelry
Pick what you know — a US size, a UK letter, or a measurement — and get every equivalent at once.
Closest standard size shown — sizes vary slightly between manufacturers.
About this tool
Ring sizes aren't standardized worldwide — the US/Canada system uses a numeric scale, the UK/Australia system uses letters, and both map onto a physical inner diameter in millimeters. This converts between all three using a standard sizing chart.
For the most accurate fit, measure an existing ring's inner diameter or wrap a strip of paper around your finger and measure its circumference, then match it here.
Tip
Fingers are slightly larger in the evening and in warm weather — measure at the end of the day for the most generous fit.