Ring Size Conversion Chart

Use the following chart for conversion of US and Canadian number sizes to the "Wheat sheaf" system of letter sizes used in Ireland, U.K. Australia, ect. Diameters and circumferences are also given in both inches and millimeters. Please note that these measurements are exact for the American system and approximate for the other sizing scales, since the intervals in each system do not correspond exactly. 

Ring sizing gauges and finger gauges as well as published charts do not always agree. Add to this that there are two conflicting methods of sizing rings so it is quite common for ring sizes to vary slightly from one workshop or jeweler to another. The ring sizing information presented here is the result of a conscientious study and comparison of various sources and is consistent with generally accepted measuring techniques. 

Rings and gauges are hard metal objects that can be measured exactly, but your finger is flesh and bone. Your finger is not round and it cannot be measured with the same degree of accuracy as the ring. At the end of the day, the right ring is one that will stay on comfortably. Average ring finger sizes may be useful as a point of reference for people who are not very good at measurements. These are offered to help you know if your calculations are reasonable.

Average adult women size 6 to 8 or L to Q
Most American jewelers 
get women's samples in size 7
Average adult man size 9 to 11 or J to W
Most American jewelers
 get men's samples in size 10 

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. 
Men take note that if you are not used to wearing a ring, the proper size will probably feel tight a first. Many men loose their wedding rings because they choose sizes that are too loose.