Country Code Systems: ISO to IOC Compared

Tap a system to see how it works.

ISO 3166

The international standard for country codes, used in domains, shipping, and official documents. It defines both 2-letter codes (like KR, US, JP) and 3-letter codes (like KOR, USA, JPN) for each country.

IOC Codes

Three-letter codes used by the International Olympic Committee to represent participating countries and territories at the Olympics. They sometimes differ from ISO codes for historical or political reasons.

FIFA Codes

Three-letter codes used by FIFA for national football teams, which also occasionally differ from both ISO and IOC codes.

International Calling Codes

Numeric prefixes assigned to each country for making international phone calls, such as +82 for South Korea or +1 for the United States and Canada.

ISO 4217 Currency Codes

A related standard that assigns 3-letter codes to currencies, such as KRW, USD, and JPY, widely used in banking and finance.

Why the same country can have different codes

Because ISO, the IOC, and FIFA are separate organizations that developed their coding systems independently and for different purposes, a country's code can differ slightly between systems β€” this is why understanding the differences is useful when reading international data or sports coverage.

Frequently Asked Questions

Why does the IOC code for a country sometimes differ from its ISO code?

The IOC established many of its codes earlier and has kept some legacy codes even after ISO standards changed, or uses codes that reflect the country's name in a different context, leading to occasional mismatches.

Which code system should I use for a website or database?

ISO 3166 is the most widely adopted standard for general-purpose use, including web domains, shipping addresses, and software development.