Wrap a strip of paper or string around the base of the finger
Mark where the ends meet
Measure the length in millimeters
Compare the measurement to a ring size chart
Measure the finger at the end of the day
Measure several times for accuracy
Make sure the ring can pass over the knuckle
Use a ring sizer tool for the most accurate result
Avoid measuring when fingers are cold or swollen
If between sizes, choose the larger size