If you have a ring that fits the desired finger, you can measure its internal diameter. To do this, place your ring on a ruler and measure the distance across the inner circle, from one inside edge to the other.

With this measurement in millimeters, check the Diameter column in our table to find the closest match. Again, if you’re between sizes, it’s best to size up.

If you don’t have a fitting ring, you can measure the circumference of your finger instead. The circumference is the total distance around your finger, and you’ll just need a piece of string, a pen, and a ruler to measure it:

Wrap a piece of string around your finger.

Mark where the string overlaps with a pen.

Lay the string flat against a ruler and measure the length up to the mark.

This length is your finger’s circumference. Check the Circumference column in our table and find the closest match in millimeters. If your measurement falls between sizes, we suggest sizing up.