Convert You Ring Size – Fast & Easy

Did you know that there are over half a dozen systems used all over the world for sizing jewelry rings?  It may seem confusing when the ring you bought while visiting Switzerland is a totally different size to the one you just chose at your local jeweler.  How can you be sure what your ring size is?  This becomes especially important when making a purchase from the growing online jewelry market.

At Mazal Diamond, we use the reliable European Standard Sizing unit for all of our rings.  We want to make the process confusion free – so if you have a ring size in a different unit, you can use our free conversion chart below or interactive feature to make the switch.  The interactive version appears on all individual jewelry pages as you shop.  Just click on Find My Size.  If your ring standard doesn’t appear, contact us and we will be happy to do the calculation.

Don’t know your ring size?  We’ve got the solution.  Visit how to size rings and we’ll show you 2 easy ways to figure it out.  To learn more about international sizing, continue reading below this chart.



The first major component in the size comes from whether it is measured in terms of diameter or circumference.  Sounds technical?  Diameter measures the inside circle from side to side.  A measurement taken from across the inside of your ring is a diameter measurement.  The circumference is a measurement of the full outside circle arch – (In case you’re wondering, it’s worked out as the diameter multiplied by “pi” or 3.14159….).  – This is why when you measure around your finger you will be giving a circumference measurement.


The second thing to consider when viewing this chart is whether the measurement is given in inches (in) such as in the USA and Canada or in millimeters (mm) such as in European countries.


The third and most confusing part is how the particular country or region chooses to assign sizes to measurements.

§  In the United States and Canada, ring sizes are specified from inches using a numerical scale, with quarter and half sizes. E.g. 0, 1/4, 1/2, 3/4, 1, 1 1/4…..

§  France, allocates ring sizes from mm using a numerical scale with half sizes while Switzerland, also gives quarter sizes. E.g. 1, 1.25, 2.5, 3.75

§  The UK system (Ireland, United Kingdom and Australia) created an alphabetical scale, with half sizes. EG. A, A1/2, B, B1/2…

§  In Japan and China, a numerical scale is given with whole sizes but it does not have straightforward correlation to diameter nor circumference. E.g. 1, 2, 3, 4….

§  The European Standard gives sizes using actual internal circumference in mm.  This is also the recognized sizing of the ISO – International Organization for Standardization. E.g.40 &1/2, 41 & 1/8, 47 & 3/4

§  The German sizing uses inside diameter in mm. E.g. 12 &3/4, 13, 13& 1/4…

Read all articles in Diamond Education, Engagement Ring Buying Guide