Find out your Ring Size
If you don't happen to know your ring size then the best option is to go to your jeweler & get it checked.
But if you feel lazy to go out then you can DIY.
Cut a thin piece of paper or cut a string and wrap it around your finger firmly. The way you would want the ring to fit.
Lay that against a ruler to measure the circumference (in mm/inches)
Please choose the ring size that is closest to your circumference if you are in-between sizes.
Then use size chart to find your ring size.