Ring Size

How can I work out the ring size?


There are several ways to measure the ring size. Essentially, it depends on whether you already have a ring which fits or not.

1. You have a well fitting ring to compare?

A) Measure the inner diameter of a ring

Take a well-fitting ring and use a ruler to measure the distance between the inside edges (the ring gauge only applies to round rings).


Enter the value here below.

Ring diameter (in mm):

Ring size =

B) Compare your ring with the ring template.

Print out our ring template. Place your ring over the circles to find the one which completely fills the inside of the ring without overlapping. Important: be sure to check the scale of the ring template when you print it off.

Print ring template

2. You have no ring for comparison:

A) Measure the ring size with our ring-sizing tool.

Order our free ring-sizing tool. Simply send us an e-mail customerservice@21DIAMONDS.co.uk

Additional information:

The fingers of the left and right hands are usually slightly different sizes. Please bear this in mind when chosing which finger to measure. Most people find that the circumference of their fingers changes during the day; normally, the fingers are thicker in the evening than in the morning. Please bear this in mind when choosing your ring size so that you have a ring that fits well the whole day.

Don’t forget that, if your 21DIAMONDS ring doesn’t fit, we offer one free alteration as part of our service. If the ring is engraved however, we need to keep 50 Pounds. Simply contact our Customer Service team and send the ring back to us with your preferred measurement.