Use a paper or string : Cut a strip of paper, approximately sized 3/4 inch wide and 4 inches long.
Wrap the paper around the base of the ring finger and make a marking at a point where the paper overlaps
The length of the paper you measure in millimeters(mm) is the circumference of your finger
Measure the diameter of the ring you already own using a ruler
Measure the ring from one inside edge to the other inside edge placing it straight
Take the measurement of the diameter in millimeters and use the measurement conversion chart below to find your perfect ring size
Ask your friends and family if they know your partner’s ring size
Borrow one of the ring from your partner’s jewellery collection, ensure that you pick up the ring she wears in the ring finger.
In case of any doubt, always choose a large ring size
If you are willing to guess and take the risk, pick a ring you can easily re- size.