Ring sizer on phone — free, no install.
Looking for a ring sizer on phone free? You're already on it. RingSize.app runs in your mobile browser — iPhone Safari, Android Chrome, anything modern. Calibrate with a credit card pressed against the screen, then place your ring on the display. The actual ring size chart on phone matches real millimetres.
Why a phone is the perfect ring sizer
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Always with you Your phone is the one screen you have everywhere. Sizing your ring should be just as portable.
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Fits credit cards perfectly A standard credit card is wider than most phone screens — ideal for screen calibration.
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Pinch-to-zoom protected We lock the calibrated scale even when you zoom, so your measurement stays accurate.
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Add to home screen Save RingSize.app to your home screen and it works like an installed app — without taking up storage.
The ring sizer on phone — 30 seconds to your size.
Calibrate once with a credit card. Then place a ring you own on the screen, or measure your finger with a paper strip. Free, no sign-up.
The main ring sizer
The full guided flow — choose method, calibrate, measure, convert.
ReferenceInternational ring size chart
US, UK, EU, JP, IN, CN — every standard, side-by-side.
ToolVirtual ring sizer
Screen-calibrated alternative to a physical ring sizer kit.
ToolRing size calculator
Convert between US, UK, EU, JP — or from raw millimetres.
GuideHow to measure ring size
Three reliable methods, ranked by accuracy.
ArticlesAll ring sizing resources
Guides, tips and tutorials for getting the right fit.