Quick Take: Ring Sizing

Cocktail rings are some of the hottest jewelry around, especially when it’s time for a slew of warm weather parties.  The only issue though: how do you know what size to get?  Once you know the basics, it’s actually pretty easy.  Check it out:      MM Measurement (diameter)        US Size                      UK Size          15.7                                                                 5                                  […]

how to size and measure rings

Cocktail rings are some of the hottest jewelry around, especially when it’s time for a slew of warm weather parties.  The only issue though: how do you know what size to get?  Once you know the basics, it’s actually pretty easy.  Check it out:

 average whole US ring sizes

   MM Measurement (diameter)        US Size                      UK Size         

15.7                                                                 5                                  J

16.5                                                                 6                                  L

17.3                                                                 7                                  N 1/2

18.2                                                                 8                                  P 1/2

18.9                                                                 9                                  R 1/2

19.8                                                                 10                                T 1/2

20.6                                                                 11                                V 1/2

21.4                                                                 12                                X 1/2

22.2                                                                 13

Although half sizes won’t be available for most costume jewelry in the United States, they do exist, and are generally made use of for wedding jewelry and custom resizing services.  Since most persons will not fall perfectly into an exact whole size, it’s important to use your judgment when rounding to the closest number, and remember that it’s always preferable to be a millimeter or two too large rather than too small.

The easiest way to measure for size if you don’t have a ring sizer is to take a piece of floss around the base of your chosen finger with moderate pressure and then measure its length against a metric ruler.  Next you’ll divide the number you got (working with millimeters) by pi, which is expressed as 3.14159.  The number this yields is the millimeter measurement of the diameter, which corresponds to your size as listed above.  Here’s an example:

 measuring and conversions for finger rings

For those who have arthritis or other issues that may cause swelling in the knuckle, measurements should be made around the knuckle area instead to be sure the ring will fit over it.  For these individuals, an adjustable ring is often easier to wear, as the size may be enlarged to slip the ring on and then re-tightened around the smaller portion of the finger underneath.