💍 Free Ring Size Ruler
Find your ring size — US, UK, EU, India. No app needed.
| Diameter (mm) | Circumference (mm) | US / Canada | UK / Australia | EU / Germany | India |
|---|
How to Use This Ring Size Ruler
There are three ways to measure your ring size using this tool, and all three work right in your browser no app, no download, no account needed.
Slide to Size
Drag the ruler until it matches the inner diameter of a ring you already own. The tool will show your size in US, UK, EU, and India formats instantly.
Enter Diameter
If you know the inner diameter of your ring in millimeters, just type it in. You’ll get all four size formats right away.
Enter Circumference
Wrap a thin strip of paper or a piece of string around your finger, mark where it overlaps, then measure that length in millimeters. Enter it here and the tool does the rest.
One tip worth keeping in mind: measure your finger at the end of the day, not in the morning. Fingers are slightly larger in the evening due to normal swelling from daily activity. If you’re in between two sizes, go a half size up a ring that’s slightly loose is much easier to adjust than one that’s too tight.
Why Ring Sizes Differ by Country
If you’ve ever tried to buy a ring online from an international store, you’ve probably noticed that size systems vary quite a bit depending on where the jeweler is based. Here’s a quick rundown:
- US & Canada use a numeric system starting from size 1. Most women’s rings fall between size 5 and 8, and most men’s rings fall between size 9 and 12.
- UK & Australia use letters A through Z, with half sizes in between. A UK size N is roughly equivalent to a US size 7.
- EU & Germany use the circumference of the finger in millimeters as the size number. An EU 54 means your finger circumference is approximately 54mm.
- India uses its own numeric scale that runs slightly differently from the US system. An India size 9 is close to a US size 7.
Our tool shows all four simultaneously, so you can shop from anywhere without having to cross-reference multiple charts.
International Ring Size Chart
The table built into the tool above covers sizes from the smallest (about 12.37mm diameter) all the way up to Z+2 (about 22.73mm diameter). If you want to find your size manually, measure the inner diameter of a ring that fits well and look it up in the chart. The most common ring sizes for women globally fall between 14mm and 17mm diameter, and for men between 18mm and 21mm.
If a ring fits perfectly on a warm day, go one size up metal contracts slightly in cold weather and a ring that was comfortable in summer can feel tight in winter.
String Method — Step by Step
This is the most accurate method if you don’t have a ring to measure from:
- Cut a thin strip of paper or use a piece of non-stretchy string, about 10cm long
- Wrap it snugly around the base of the finger you want to wear the ring on
- Mark the point where the paper or string overlaps with a pen
- Lay it flat and measure the length from the end to your mark in millimeters
- Enter that number into the circumference field in the tool above
Make sure the paper or string is snug but not tight you should be able to slip it off without resistance. That’s the same fit you want from a ring.
Frequently Asked Questions
Very accurate, as long as you measure correctly. The slider method works well if you have a ring that fits well to compare against. The string method is the most reliable if you don’t have an existing ring handy. If you’re between two sizes, always size up.
Go with the larger size. A ring that’s slightly too big can be resized by a jeweler for a small fee. A ring that’s too small is harder and sometimes impossible to resize depending on the metal and design.
Yes, it can. Weight changes, pregnancy, temperature, and age all affect finger size. If you haven’t measured in a while, it’s worth checking again before buying.
Yes, it works on any phone or tablet browser. No app download needed.
For women, US size 6 to 7 (EU 51–54) is the most common range. For men, US size 10 to 11 (EU 62–64) is most typical though this varies significantly by region and individual.