Wrap a strip of paper or string around the base of your finger
Mark where the ends meet
Measure the length with a ruler in millimeters
Compare the measurement to a ring size chart
Measure the same finger at the end of the day
Measure when your hands are warm
Repeat the measurement 2 to 3 times for accuracy
Use a ring that already fits well and measure its inner diameter
Compare the inner diameter to a ring size chart
Check the size on the exact finger you plan to wear the ring on
If between sizes, choose the larger size