Using a ring size chart is among the most simplest ways to determine your ring size. First wrap a strip of paper or string around your finger and hold it taut with no overlap. Snip or mark the string when two ends meet and then measure the paper or string against a ruler to the nearest 1/16th inch. Generally 1/16th inch increases the ring size by 1/2 an inch Find the measurement on the chart below to determine ring size. It is a good idea to wrap the paper around the knuckles as well as well as the base of the finger. This way modifications can be made so that the ring is not too tight over the knuckles or too loose at the base of the finger.