Ring Size Converter
Convert a ring's inner circumference in millimetres to a US ring size.
Quick answer: enter your details below and click Convert Ring Size — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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Enter your details below.
How to use
- Enter the inner circumference in millimetres.
- Click Convert Ring Size.
- Read the nearest US ring size.
About this tool
Enter the inner circumference of a ring in millimetres, and the tool finds the nearest standard US ring size from a reference table. Ring sizes vary slightly by country and by ring width, so treat the result as a guide and confirm with a jeweller for an expensive ring.
Frequently asked questions
Why is the result approximate?
Because the tool picks the nearest table value, and wide bands and different countries size slightly differently.
Should fingers be measured warm or cold?
Warm, at the end of the day, when fingers are at their largest — a ring that fits cold fingers can feel tight later.