About Ring-Sizer.Online

One tool, done properly.

Ring-Sizer.Online exists to answer a single question well: what is my ring size? Most people don't own a jeweller's mandrel, and printable sizing charts fail the moment a printer scales the page by a few percent. A screen, on the other hand, can be calibrated precisely — which is the idea this site is built on.

You calibrate once against a bank card (85.60 mm wide everywhere in the world), and from then on every circle drawn on this page is true to real-world size. Place a ring on the screen, match it to the circle, and read your size in US, UK, EU, Japanese and Indian systems at once.

How this site works

• Everything runs in your browser. There is no account, no upload, and no server doing measurements. Your calibration is stored only on your own device.
• It's free. The site is supported by advertising, which keeps the tool free for everyone.
• It's maintained. Size charts are checked against published jeweller standards, and the tool is tested across common phone and desktop screens. Spot an error? Tell us — we fix things.

Who runs it

Ring-Sizer.Online is an independent web project built and maintained by a small publisher of free online utilities, based in Himachal Pradesh, India, serving visitors worldwide. It is not affiliated with any jewellery brand or retailer.