⚠ Important: For 100% Ring Size Accuracy, visit your local jeweler for an in-person measurement. All tools on this site are estimates only.
Interactive Tool

Ring Size Calculator

Enter your finger circumference or ring diameter in mm or inches — get your ring size in every major system instantly.

Enter your finger measurement below and select whether it's the circumference (measured around your finger) or diameter (measured across a ring). Select your region and click Find My Size.

How to measure: Wrap a strip of paper around the base of your ring finger. Mark where it overlaps. Measure the length in mm — this is your circumference. Alternatively, measure the inside diameter of a ring that fits correctly.

Enter your measurement and click Find My Ring Size

Full Size Chart

USUKEUJapanSwissDiameter (mm)Circumference (mm)
3F444414.144.2
3.5G455514.545.6
4H46.576.514.946.8
4.5I488815.348.0
5J499915.749.3
5.5K50.51110.516.150.6
6L51.51211.516.551.9
6.5M53131316.953.2
7N54141417.354.4
7.5O55.51615.517.755.7
8P57171718.257.2
8.5Q58181818.558.2
9R59191918.959.3
9.5S61212119.461.0
10T62222219.862.2
10.5U63.52423.520.263.5
11V65252520.765.0
11.5W66262621.166.2
12X67.52827.521.567.5
12.5Y68.52928.521.968.8
13Z70303022.370.1
14Z+271313122.771.3