The easiest way is to measure a ring that already fits the right finger: its inside diameter gives the size. Otherwise, wrap a strip of paper around the base of the finger and measure its length.
Measure at the end of the day
Fingers are a little larger in the evening and in warm weather. A band wider than 4 mm usually needs a quarter to a half size more.
A sample article for the Gemelune theme demo. The pieces and collections mentioned are fictional.


