For calculation purposes if you are unsure what your ring size is (or the ring size of the person you are buying for), please use either of the methods below to calculate. It is simple to get the measurement right, as you can see:

Method a). Wrap a piece of string or a strip of paper around your finger (around the knuckle area is preferred). Mark the point where the two ends meet and measure the string or paper against a ruler to get the circumference of your finger. If you are using a conversion ring size chart you can divide the circumference by 3.14 which will provide you with the diameter of your ring/finger.

Method b). Measure the inside diameter of a ring that you already own. Use a ruler or a pair of callipers. Compare the diameter of your ring against the table provided below.

Now you have your UK ring size.