Take a piece of thread or string and place it around your wrist, right where you will be wearing the bracelet. Make sure to mark the point where the end of the string meets the rest of the string.
Remove the string from your wrist and measure its length on a ruler.
With the exact measurement, look for the corresponding size in the table.
Take a thin piece of thread or string and place it on the part of your finger where you will wear the ring. Bring the ends of the string together until they touch, so that it fits snugly around your finger.
Mark the exact point where the string overlaps. Remove the string and measure that length with a ruler.