1.
Wrap a thin strip of paper around the base of your finger. If you have larger knuckles, measure both. (You may want to choose a size between the two to allow the ring to slip on comfortably.)
2. Mark the spot where the paper meets.
3. Measure the paper's distance with a ruler.
4. Use the chart to determine your ring size.
And that's how you measure your ring size, super easy. :)