Ring sizing is most accurate when performed by measuring the actual inner circumference of the ring finger to determine the correct ring size.
Instead of having to send your brand new ring back to be
upsized or downsized on the very day you receive it; have your finger sized
correctly before you order your ring.
You would be best served to simply decide which finger on which you will be wearing your ring and then stop in at your local jewelry store, or or department store which carries jewelry, so you can determine ring size.
Printable Ring Size Chart - Inaccurate
Some jewelry websites provide a printable ring size chart which you can print out, however variables can occur in the way your printer rasterizes (compiles) the data to print the chart.
Every printer prints data a little bit differently.
Even if the paper ring size chart prints perfectly, (and you cut out the hole, perfectly...with an Exacto knife...which is difficult), when you place your finger inside the hole, if you bend or stretch the paper even a fraction of an inch, your ring size will be incorrect.
String Method - Inaccurate
Some jewelry sizing websites describe how you can accurately perform jewelry sizing using a piece of string. Please...don't.
String stretches and is very difficult to use to accurately determine the size of your finger. Remember that your ring has to pass over your knuckle...which is probably larger in size than the base of your finger.
Therefore, using string to measure the base
of your finger is very unreliable.
Time of Day
Fingers change size according to temperature, time of day, humidity and your diet. For the best fit, take measurements at room temperature (not after showering, being outdoors in the winter, vigorous exercise, etc.).
It is best to size your finger toward the end of the day when your fingers are typically largest.
International Ring Sizes
Different countries size rings using different systems. If you purchase a ring from another country, be sure to cross-reference it against an international ring size chart so you will be able to choose the correct ring size that equates to the ring sizing chart in your own country.
In the United States and Canada, ring sizes are between size 0 and size 16 and include half sizes and quarter sizes.
Standard U.S. men's ring sizes are between a size 8 and a size 14.
In the United Kingdom, Ireland and Australia, ring sizes are between size A and size Z4 and include half sizes.
In China and Japan, ring sizes are between size 1 and size 27.
In Switzerland, ring sizes are between size 1.5 and size 28.75 and includes half and quarter sizes.
In France and Germany, the actual inner circumference, measured in mm (millimeters) is used.
Measure the Correct Finger For Jewelry Sizing
Do not assume that the fingers on your left hand are the same size as the fingers on your right hand. The finger size of your dominant hand is usually larger than on your non-dominant hand, sometimes as much as half a size.
Always measure the finger that you will actually be wearing the ring upon.
Not all rings can be re-sized.
Jewelers cannot resize rings that are gold-plated (inexpensive) rings nor rings made of tungsten steel or titanium.
Rings with stones in them, those with intricate mountings, and those that are very thin or very wide may not be able to be re-sized.
Taking a little extra time to perform ring sizing before you purchase a ring is well worth the effort and may save you from disappointment or having to pay to have the ring re-sized.