How to measure your ring finger correctly
Cut a thin strip of paper and place it underneath your chosen ring finger as per the picture below.
Fold one side of the paper over the top of your finger to create a loop, this loop must fit your finger comfortably. Once you have done this grab a pen and mark the opposite side as per the picture below.
Next grab a ruler and place your strip along side so you can write down your circumference in mm (millimetres)
Look at this chart, and convert your circumference measurement to the nearest ring size.