mm to Ring Size Converter

You can easily determine your ring size by wrapping the knuckle of your finger using a non-stretchable string or a strip of paper and marking where one of its ends falls, as shown in the image below:

With a ruler, measure the length of that string or paper in millimeters and select the closest value available in the drop-down list of our mm-to-ring size converter's Inside circumference variable.

Our tool will display its corresponding US & Canada ring size and other equivalent ring sizes (used in UK & Australia, France & Russia, Germany, Switzerland, or Japan) if applicable.

If you want to find the ring size of another ring, you can measure its diameter by aligning it over a ruler from the zero mark to a reading on the ruler. Then, select the closest value available in the Inside diameter variable of our tool.

After measuring your finger, you can also use the mm-to-ring size conversion chart below:

For example, you find out that you can wrap your finger with a 54.0 mm strip of paper end-to-end. From the chart above, the next inside circumference measurement of a ring size available is 54.51 mm. That means your finger ring size would be size 7 (US).

🙋 Remember that, since our knuckles are not perfectly round, we choose the next one and not the closest smaller ring size.

If you found our mm-to-ring size converter useful, perhaps you may also enjoy reading our other related tools listed below:

• cm to ring size converter;
• Inches to ring size converter; and
• cm to mm ring size converter.

Read more useful tips for determining your proper ring size in our ring size converter. 😊