About
Free sizing tools that check their own accuracy, starting with rings.
The problem
Finding your ring size at home sounds easy: print a chart, or hold a ring against your screen. The trouble is that neither is reliably the size it claims. Printers shrink pages to fit their margins. Screens all have different pixel sizes. And one US ring size is less than a millimetre, so small errors become the wrong ring.
Most printable sizers online are a PDF and the words "print at 100%". There is no way to tell whether that worked, and nothing to do if it did not.
What is different here
Every sizer on this site checks itself before you trust it. The printable ring sizer has a 100 mm bar to measure, and if your printer got it wrong, it builds a corrected PDF. The on-screen sizer uses a bank card, which is the same size everywhere in the world, to learn the real size of your screen.
The idea comes from an earlier project, Pattern Tiler, which helps people print sewing patterns at exactly the right scale.
Where the numbers come from
Every size is calculated from the published definition of each system: the US inch scale (0.458 in + 0.032 in per size), the British Standard for UK letter sizes, ISO 8653 for European sizes, and the Japanese ring gauge. Nothing is copied from another chart, so every page here agrees with every other. The ring size converter lists the formulas.
How it works, and your privacy
Everything runs in your browser. The PDF is built on your device, and your measurements are never sent anywhere. There is no account and nothing to sign up for.
Who builds it
SizeCheck is built and maintained by Nageshwar TN. It is independent and not affiliated with any jeweller or ring brand.
If a tool gives you a size that turns out wrong, I would like to know. Please get in touch via the contact page.