Ring size is typically measured in whole numbers. For example, someone with small fingers may have a ring size of 4 while someone with large fingers may have a ring size of 10. If you want to measure for a ring size in centimeters you can do so and then look at a chart to find out the exact numerical ring size you have. This helps ensure you buy ring in the right size for your fingers.
Wrap a flexible tape measure around your ring finger to find the size of your finger, in centimeters. Do not wrap the tape measure tightly around your finger. For the most accurate measurement, wrap the tape measure at the level of tightness ideal for wearing a ring on that finger.
Measure your finger again to double-check your information from Step 1. It is very important to measure your ring finger a second time, as this information needs to be as accurate as possible to ensure you purchase a ring that will sit comfortably on your finger. If you measured accurately in Step 1, the second measurement should be identical to the first.
Compare the centimeter width of your ring finger to a ring sizing chart to determine the appropriate ring size for your finger. For example, if your ring finger was 5 centimeters, you have a ring size of 4.