Currency

Great! This is going to be easy!  

You can do any of the following:

  1. Take your ring to a local jewelry store and have them size it on a standardized mandrel (please don’t use one from a local craft store as they are often not standardized and lead to bad results).
  2. Use a ruler or, better yet, a digital caliper, to measure the inside diameter. You may want to measure a few areas around the ring in case it is slightly oval, and take the average of the measured sizes. 
  3. Use a site like findmyringsize.com for their digital measurement tools