To measure your ring size
Wrap a thin strip of paper or piece of string around the base of the finger you want to measure. With a pen, mark the point on the paper or string where it overlaps, forming a circle on the finger. Measure the length of the paper or string using a flat ruler, from the starting point to the pen mark.
The most common ring sizes for women are 6 -16.5 mm 6.5 -16.9 mm and 7 -17.3 mm
For men, the most common sizes are 10 -19.8 mm 10.5 -20.2 mm- and 11 -20.6 mm
Sizes are given in millimeters based on the inner circumference of the ring.