Ring Size Calculator
Convert ring circumference and diameter to common sizes.
Ring Size Calculator
Enter an inside diameter or finger circumference; everything is calculated locally in your browser.
Conversion result
Closest standard size: —
- US
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- UK / AU
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- EU / ISO
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- Japan
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- Inside diameter
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- Finger circumference
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The chart uses common standard values; brands may vary slightly. For a wide band, consider going up about ¼–½ size.
Measure a ring on your screen
Calibrate your screen with a bank card, then match your ring to the circle.
Credit-card calibration box (85.6mm)
Drag until the dashed rectangle is the same size as a physical card.
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Place an existing ring flat on the screen and drag until the circle fills the inside of the ring.