Digital ring sizer · screen-calibrated
A digital ring sizer that's actually accurate.
Plastic ring sizer kits cost £8 and take a week to arrive. Printable charts are scaled wrong by every printer. RingSize.app is a free digital ring sizer that calibrates to your screen using a credit card, then shows the actual ring size on screen at real millimetre scale.
How our digital ring sizer compares
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vs plastic ring sizer kits Same accuracy, instant, free. No shipping, no waste.
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vs printable charts Printers re-scale silently. Our digital ring sizer calibrates to the exact pixels on your screen, so size is accurate even at 87.5% browser zoom.
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vs other digital ring sizer apps No app to download, no permissions to grant, no account to create.
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vs visiting a jeweller Same precision, on demand, at home — and we save your size for later.
Try it now
The digital ring sizer — 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.
Tool
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.