Using the calculator
Enter Measurement type, Measurement. Estimate US ring size from finger circumference or inside ring diameter in millimeters.
FASHION & SEWING
Ring Size Calculator
Estimate US ring size from finger circumference or inside ring diameter in millimeters.
mm
Circumference—
Diameter—
Estimated US ring size—
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How to use this calculator
Reading the result
The result shows uS ring size from finger circumference or inside ring diameter in millimeters.
How it is calculated
Diameter is circumference divided by pi. The US size estimate follows a standard circumference based approximation and rounds to a quarter size.
Results are estimates based on the values entered. Review the Methodology and Calculator Disclaimer for important limitations.