mm to Ring Size Converter

If you're finding a way to convert the circumference or diameter of a finger in millimeters to its corresponding ring size, then this mm-to-ring size converter is for you. With this calculator, you can find the correct ring size by measuring the length of a string or a strip of paper you can wrap around any of your fingers.

In this calculator, you will learn the following:

• How to find your ring size using this mm-to-ring size converter;
• How to determine the ring size using the mm-to-ring size chart; and
• Some frequently asked questions about the conversion from mm to ring size.

Keep on reading to start discovering your fingers' ring sizes. 💍

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 17 (US).

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. 😊

To convert a measurement of your finger in millimeters to a ring size:

1. Take a string and wrap it once around the finger you want to measure.
2. Mark the string where it overlaps over itself.
3. Using a ruler, measure the length of the string you marked.
4. Check your ring supplier's chart for your ring size.
5. You can also divide the string's length by π or 3.14 if the supplier's chart asks for the equivalent diameter of your ring size.

The 5 3/8 US and Canada ring size has an inside diameter of 16 millimeters. In UK and Australia, find the size K 1/2 if your ring measures 16 millimeters in diameter.