Ring Size Converter
Ring sizes from circumference or diameter — US, EU and UK scales.
The Ring Size Converter maps ring measurements to the three common sizing scales: US/Canada, EU (used across continental Europe) and UK/Australia. Enter the inner circumference in millimeters — or the diameter — and read your size on all scales.
Getting a ring size right matters most when it is a surprise: you cannot ask the recipient, so a measured ring or a careful string measurement of an existing ring is the standard trick. Convert that circumference here and compare with the jeweler's chart before committing.
Conversions use the standard linear fits between sizing systems. Fit varies with finger shape, temperature (fingers swell in heat) and band width, so treat the number as the starting point the jeweler will confirm. Runs locally.
US / Canada
6.0
EU (incl. France/Germany)
16.0
UK / Australia
5.7
Inner diameter
17.2 mm
circumference 54.0 mm
Approximate linear fits over standard sizing charts. Best practice: wrap a string or paper strip around the finger, measure against a ruler in mm, and compare with a jeweler — knuckle and temperature affect fit.
How to use the Ring Size Converter
- Wrap a string or paper strip around the finger (or an existing ring).
- Measure the length in millimeters — that is the circumference.
- Enter it (or the inner diameter) in the converter.
- Read US, EU and UK sizes.
- Confirm with a jeweler's sizer for the final call.
Frequently asked questions
How do I measure my ring size at home?
Wrap a thin strip of paper or string around the finger (snug but sliding over the knuckle), mark where it overlaps, and measure that length in mm — that is the circumference this converter needs.
What is a typical ring size?
Women's rings commonly fall around US 5–7 (circumference ~49–54 mm); men's around US 9–11 (~59–65 mm). Hands vary widely, so measurement beats averages.
Why measure an existing ring instead of the finger?
For gifts, an existing ring is the only clue you can access secretly — measure its inner diameter across the widest point. Finger measurement works when the person can try it directly.
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