Find a likely ring size using a ring that already fits.
Calibrate the screen with a card or coin, match the ring's inner edge, and get an estimate in millimeters and Brazilian size. Free, with no camera or account.
Read the guide firstStep 1 of 3
Everything happens on this screen.
Choose a physical reference
No card data is read or sent.
Before buying
Ring size is a purchase reference, not a fit guarantee. Band width and shape also make a difference.
- Measure a familiar ring
Use a round ring that feels comfortable on the same finger and hand.
- Match only the inner edge
The ring's outside thickness is not part of the diameter used by the sizer.
- Check the jeweler's chart
Brands and designs can vary slightly. Confirm in person before an important purchase.
Questions about measuring
Can a phone measure ring size?
Yes. After calibrating the screen with an object of known size, place a ring over the circle. The result remains an estimate.
Does the sizer use the camera?
No. It relies on the calibrated on-screen size and never asks for camera access.
Can I measure my finger with string?
This tool is designed for a ring that already fits or a known millimeter measurement. String and paper can stretch or tighten and increase error.
What should I save?
Keep the likely size with the diameter, person, finger and date. That context is more useful than a number alone.
Continue in the app
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