Ring size calculator · all regions
Free ring size calculator — every region at once.
Got a measurement in millimetres but need the US size? Or have a UK size and need EU? Our ring size calculator converts between every major standard — US, UK, EU, JP, IN, CN — and shows the actual ring size on screen so you can double-check before buying.
What this ring size calculator does
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Converts every direction US ↔ UK ↔ EU ↔ JP. Inner diameter ↔ circumference. Pick any input, get every other unit.
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Visualises the result The calculator doesn't just spit numbers — it shows a calibrated ring at the actual size on screen so you can confirm with a physical ring.
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Quarter-size precision Covers US 3 through 13 in 0.25 increments — the same precision a jeweller uses.
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Free, no sign-up, no maths No fiddly formulas, no half-size confusion.
Try it now
The ring size calculator — 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.