1. Cut a piece of string about 10-12cm long.
  2. Wrap the string tightly around your desired finger.
  3. Mark the point where the string overlaps itself with a marker.
  4. Lay the string on a flat surface and use a ruler to measure the distance from the end of the string to the marking you made, in millimetres. This will give you a measurement of the circumference of your finger.
  5. Using the below chart, convert your measurement into a standard US numeral ring size.  
  6. If you are in between two sizes, it is always best to round up rather than down.
  7. If you already have rings that fit well, you don’t even have to take a finger measurement or worry about millimeters. Simply use the ring size you have that fits you well and use that as a reference when buying your ring.