Take a piece of string or a thin strip of paper and coil it around the base of your finger.
Mark the point where it overlaps with a pen.
Measure in millimetres the length from the starting point of the string/paper to the pen mark. You will now have the circumference measurement of your finger.
Divide this number by 3.14 to determine the diameter of the ring you need.
Click on step 5 to view the Size Me Up chart to find your ring size.
If you are buying a ring for someone else you can use the same procedure. Simply take a ring belonging to them and place it on your own finger. Use the string/paper technique to measure the circumference of the finger that their ring fits or the place on your finger that the ring rests. Alternatively, you can take any existing ring to a local jeweller to be measured.