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Your Guide to International Ring Sizing

Written by Anna Currell
December 6, 2022

Knowing your ring size is one of the most important parts of shopping for a new ring. An ill-fitting ring can be incredibly frustrating; it can fall off, get stuck on your finger, or just gather dust at the back of your jewelry box. What makes finding the perfect size even more complicated is the different ring sizing systems used internationally. Some sizes are numbers, some are letters — what do they mean, and how do they correspond to each other? In this article, we’ll explore the different sizing systems and explain how to find and convert your size so you can find a perfect fit no matter where in the world you shop. 

The Different Ring Sizing Systems

Ring sizes are measured differently in different countries and regions of the world. Some systems use letters of the alphabet while others use numerical values, but each system measures differently even within those categories. For instance, a ring with a 51.9 mm circumference would be a size 6 ring in the US, an L ½ in Australia, and a size 11 in Japan. How did all of these regions arrive at these different systems? And how can you determine which size to get in a country that uses a system you’ve never seen?

Even though the sizing systems are all different, they all take the same starting point; the International Organization for Standardization (ISO) developed the internationally recognized way to measure the inside circumference of the ring in millimeters. Every ring size, regardless of which system it uses, begins with this measurement. 

Then the millimeter measurement is converted into various sizing systems. It's human nature to deal in smaller, more manageable numbers, so instead of requiring consumers to memorize the millimeter circumference of each finger on each hand, sizing systems let them track a single letter or digit. For instance, many European countries use a system that subtracts 40 from the millimeter measurement, which gives a much smaller number to work with — a 50 mm circumference is a size 5 ring in this system.  

While each region has found a system that works locally, not every region adjusted to the same format. It's not so much about rhyme and reason as it is about different geographic regions doing things their own way based on localized standards of measurement (and of commerce), kind of like the imperial and metric systems. This makes shopping for rings harder, especially now that we mostly shop online. But don’t worry — there’s a simple way to find and convert your ring size.

How to Measure Ring Size

The best way to determine your ring size is to take a piece of paper, wrap it around your finger, mark the point where the paper overlaps on itself, and measure that length using a ruler or a tape measure. Write down the measurement in millimeters, and then use a sizing chart to find which ring size correlates to that measurement. 

For a more detailed overview of the ring sizing process, watch this video tutorial:

International Ring Sizing Conversion Chart

Now you’re ready for our handy conversion chart outlining the different ring sizing systems in use around the world. These measurements apply to everyone, so there’s no separation between men’s or women’s sizes (like with shoes, for example). To find your ring size in a different system (say, if you live in Canada but want to purchase an Australian-made ring), start by measuring your finger using the method above. Then match your measurement to your desired region’s ring size on this chart. 

44.2 mm3F4-4.2
44.8 mm3.25F 1/2--4.8
45.5 mm3.5G555.5
46.1 mm3.75G 1/2666.1
46.8 mm4H7-6.8
47.4 mm4.25H 1/2-77.4
48.0 mm4.5I888
48.7 mm4.75J-98.7
49.3 mm5J 1/29-9.3
50.0 mm5.25K-1010
50.6 mm5.5K 1/210-10.6
51.2 mm5.75L-1111.2
51.9 mm6L 1/2111211.9
52.5 mm6.25M12-12.5
53.1 mm6.5M 1/2131313.1
53.8 mm6.75N--13.8
54.4 mm7N 1/2141414.4
55.1 mm7.25O-1515.1
55.7 mm7.5O 1/215-15.7
56.3 mm7.75P-1616.3
57.0 mm8P 1/2161717
57.6 mm8.25P 3/4--17.6
58.3 mm8.5Q 1/4171818.3
58.9 mm8.75R-1918.9
59.5 mm9R 1/218-19.5
60.2 mm9.25S-2020.2
60.8 mm9.5S 1/2192120.8
61.4 mm9.75T--21.4
62.1 mm10T 1/2202222.1
62.7 mm10.25U212322.7
63.4 mm10.5U 1/222-23.4
64.0 mm10.75V-2424.0
64.6 mm11V 1/2232524.6
65.3 mm11.25W--25.3
65.9 mm11.5W 1/2242625.9
66.6 mm11.75X--26.6
67.2 mm12X 1/2252727.2
67.8 mm12.25Y-2827.8
68.5 mm12.5Y 1/226-28.5
69.1 mm12.75Z-2929.1
69.7 mm13Z 1/2273029.7
70.4 mm13.25Z1--30.4
71.0 mm13.5--3131.0
71.7 mm13.75Z2-3231.7
72.3 mm14Z3--32.3
72.9 mm14.25--3332.9
73.6 mm14.5Z4--33.6
74.2 mm14.75--3434.2
74.8 mm15--3534.8

Download Chart Here

When you shop for clothing, size “M” on the label may mean something very different from brand to brand. The same is true for ring sizing. This chart can help you estimate your size across different systems, but you should always consult with a brand and check their sizing details against your circumference measurement before you make a purchase.

Now that you know how to find your ring size in any sizing system, you can shop for rings with confidence anywhere in the world. If you end up with a ring that’s the wrong size, you can always get it resized. Just send it in to our team of expert jewelers at Quick Jewelry Repairs; we’ll be happy to help you get the right fit. Our state-of-the-art repair facilities are based in New York City, but our safe and secure mail-in repair process makes it easy for you to send us your jewelry from anywhere. Tell us all the details about your ring and how you’d like to have it resized so we can craft a perfect fit right away.

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