It wasn’t until I saw and answered a question at Quora, that I realized most ring size conversion charts that you find online are mostly inaccurate. Some are so bad that they are very misleading and hard to understand. There doesn’t seem to be any International standard and most website owners are copying details from other sites purely to have some information available. After some research I discovered that there are no less than four accurate systems in current use:
The European Ring Size Standard ISO 8653:2016
This is the official system in place for the measurement of rings and is used in much of Europe. It corresponds directly to the inside circumference of a ring and quoted in millimeters. Countries that are currently using this system include the following:
Other European countries use the same system but instead subtract 40 from the original measurement. Commonly the following countries use the adapted version of ISO 8653:2016:
- The Netherlands
From the above information it can be said that a ring size 50 in France is equivalent to a size 10 in Spain.
The American and Canadian Ring Sizing System.
The US standard for measuring rings and indeed fingers is also based on measurement of the inside circumference of a ring. However this system is very different to the European standard above and this is where the confusion begins.
Quarter and half sizes are used in a numerical scale. Each full size is increased by 2.55 mm in inside circumference.
This standard is widely used by many companies around the world and includes Mexico.
So now we have no less than two systems in place but it doesn’t stop there.
UK and Asia
The United Kingdom, Ireland and Australia use a system of letters A-Z including half sizes. These loosely correspond with the American system and most companies featured at Ringmania use this system. The lettering system is also used in South Africa.
If that is not enough, Asian countries such as India, China and Japan use a sizing system that seems to follow no kind of linear measurement. However, the Asian system is actually based on diameter and countries using it are listed here:
- South America
For the reasons mentioned above, I have had to update the ring size page at Ringmania with a new chart. Previously I had just copied information from other websites as everyone else does. I felt that this was not good enough and have painstakingly created my own International Ring Size Conversion Chart which is based purely on measurement. Here is the prototype version below and please let me know if you spot any mistakes. I will be happy to learn more so I can provide the best and most accurate information. Click anywhere on the chart to see it at the main website with full information.