Measure your finger:
1. Warp a piece of string or paper strip around the base of your finger.
2. Mark the string or paper where it overlaps to form a complete circle.
3. Measure the length of the section of string or paper where it overlaps around the finger.
4. Compare your measurement with this chart to determine your ring size.
Finger sizes sometimes do not correspond to body size. Finger sizes also are prone to change with temperature, humidity, exercise, what you have been eating, time of day, time of the month, pregnancy and other factors. Dominant hand is usually 1/2 size larger, so if you are right handed and have a size 7 ring that fits the left hand it is reasonable to guess that a 7 1/2 will fit the right hand. Quarter sizes are offered to help you get the best fit, however quarter sizes make more difference on smaller fingers than on large fingers.
The best size is usually the ring that fits snugly and gives a little resistance when you take it off. Wider rings should be a little looser that narrow rings.