On-screen ring sizer
Measure a ring you already own, right on your screen. Calibrate once with a credit card, then match the circle to the inside of your ring.
- Published charts cross-checked
- No sign-up
- Mobile-first
- Reviewed sources
Step 1 - Calibrate your screen
Lay a credit or ID card flat on the box below - long side across - and drag the slider until the box is exactly the size of your card (85.6 x 54 mm).
The card cannot fit at full width here. Rotate to landscape or use the printable sizer. Print
Calibration: - · · saved
Step 2 - Measure your ring
Place a ring you own flat on the screen, then drag the circle's edge (or use the slider) until it sits just inside the band.
Why this size?
Calculated dimensions are rounded chart values, not a measured accuracy guarantee. Ruler placement, print scale, screen calibration and the finger can change the result. Confirm with a physical sizer before ordering.
No ring to measure? Use the paper-strip method or the printable sizer. Measure · Print
Send this sizer to your phone
Scanning from a desktop or laptop opens this calibrated sizer on your phone, where placing a ring on the screen is usually easier.
Frequently asked questions
How does an on-screen ring sizer work?
First you calibrate the screen using a standard credit card (85.6 mm wide) so the page knows your display's real size. Then you place a ring you own on the screen and resize the on-screen circle until it matches the ring's inside.
Is an on-screen ring sizer accurate?
Calculated dimensions are rounded chart values, not a measured accuracy guarantee. Ruler placement, print scale, screen calibration and the finger can change the result. Confirm with a physical sizer before ordering.
Do I need to install anything?
No. It runs in your browser, with no app and no sign-up. You can add it to your home screen to use it offline.
Prefer paper? Use the printable sizer. Have a measurement already? Try the converter. Print · Converter