Should you wish to buy a ring, you’ll need to give me your ring size
For the most accurate result, I suggest going to a jeweller and having them measure your ring size.
Here is a DIY method:
Take a piece of string, ribbon, thread, or a thin strip of paper and wrap it around your finger, close to the knuckle.
With a pen, carefully mark the spot where the string overlaps with its end and either hold it up to a ruler that has millimeter measurements
Use the chart at this website to determine your size: http://www.ringsizes.co/