The most accurate free ring size calculator on the web — built with jewelers, refined for engagement rings, and trusted by millions before they buy.
Use a string, an existing ring, or our printable sizer — the calculator cross-checks your input against jeweler-verified charts.
Every measurement is checked against mandrel-verified circumference data across 8 international sizing systems.
Every detail — from the measuring method to the chart data — is designed around one goal: getting your size right the first time.
Cross-verified against mandrel-based jeweler standards for a result you can trust before you buy.
Convert instantly between US, UK, EU, Japan, Australia, Canada and Swiss sizing systems.
Download a true-to-scale PDF sizer you can print and use at home in under two minutes.
Every tool is built mobile-first, so you can size a finger from anywhere, on any device.
No paywalls, no sign-up, no email required — just an accurate size, every time.
Sizing data reviewed against real bridal and fine-jewelry mandrel measurements.
Buying internationally or gifting abroad? Convert your size instantly across the world's major sizing standards.
Wrap a string, strip of paper, or your printable sizer snugly around the base of your finger.
Match your measurement against our jeweler-verified sizing chart, or let the calculator do it instantly.
Receive your precise size, converted across every major international sizing system.
A 60-second walkthrough of measuring, comparing, and getting your exact ring size.
The calculator is built mobile-first, so measuring is just as easy from your phone as it is on desktop — no app to download.
Switch between millimeters and measure by diameter or circumference — whichever you have on hand.
Match your ring or finger measurement against the on-screen guide for a precise read.
Instantly view your size across US, UK, EU, Japan, Australia, Canada, and Switzerland.
Our true-to-scale printable ring sizer lets you find your size at home, no app or account needed — just a sheet of paper and two minutes.
Download Printable GuideEverything you need to buy — or gift — the right ring, written with jewelers and reviewed for accuracy.
Every size, every system, side by side.
How to convert sizes when buying abroad.
A step-by-step walkthrough with photos.
Time of day, temperature, and finger width.
What to know about cut, size, and fit.
50+ articles on sizing & buying →
I proposed with a ring sized entirely from this calculator — she said it fit perfectly on the first try.
As a jeweler I recommend this to clients ordering resizes remotely. It's the most reliable free tool I've found.
We used the printable sizer for a surprise anniversary gift — accurate down to the half size.
Wrap a non-stretch string or paper strip snugly around the base of your finger, mark where it overlaps, then measure the length in millimeters and compare it to our sizing chart — or let the calculator convert it automatically.
Yes. The US, UK, EU, Japan, Australia, Canada, and Switzerland each use different sizing scales. Our converter maps your size across all seven systems instantly.
Yes, provided it's printed at 100% scale with no "fit to page" scaling. Our PDF includes a built-in ruler so you can confirm the print size before measuring.
Fingers are typically smallest in the morning and largest in the evening or heat. For the most reliable result, measure at the end of the day at normal room temperature.
Yes — the calculator, size chart, converter, and printable guide are completely free, with no sign-up or email required.
No account. No guesswork. Just an accurate size you can shop with confidently.