What is an ISO 3166-1 alpha-2 code?

It is the two-letter country code defined by the ISO 3166 standard, such as GB for the United Kingdom or US for the United States. It is the most widely used country code, appearing in country domains, language tags, and countless APIs.

Is the alpha-2 code the same as the country internet domain?

Almost always, yes. Country-code top-level domains are based on ISO 3166-1 alpha-2 codes, so .fr is France and .de is Germany. The notable exception is the United Kingdom, whose code is GB but whose domain is .uk for historical reasons.

Why does the United Kingdom use GB and not UK?

ISO 3166 assigns GB to the United Kingdom of Great Britain and Northern Ireland. UK is exceptionally reserved by ISO but is not the official code, although the .uk domain uses it. For data interchange, use GB.

How is alpha-2 different from alpha-3 and numeric codes?

All three identify the same country. Alpha-2 is two letters (GB), alpha-3 is three letters (GBR) and is more readable, and the numeric code (826) is language-independent. Use whichever your system requires.

Does the search send my input anywhere?

No. The full country table is built into the tool and the search runs entirely in your browser, so nothing you type is transmitted.

ISO 3166 Alpha-2 Country Code Lookup

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The ISO 3166-1 alpha-2 standard gives every country a two-letter code, and those codes turn up everywhere: in country-code top-level domains, in locale tags like en-GB, and as the country field in countless APIs and databases. This tool finds the alpha-2 code for any country and shows its matching alpha-3 and numeric codes.

How it works

ISO 3166-1 maintains three parallel codes for each country: a two-letter alpha-2 code, a three-letter alpha-3 code, and a three-digit numeric code. The alpha-2 code is the most common because it is short and was adopted as the basis for country-code top-level domains. The tool matches your text against both the alpha-2 code and the country name, so you can search either way.

One historical quirk is worth knowing: the United Kingdom’s official alpha-2 code is GB, even though its internet domain is .uk. When a system asks for an ISO country code, use GB.

Tips and example

To find a country’s code, type its name — searching Georgia returns GE. To go the other way, type the code you have, such as JP, to confirm it is Japan. The result line also shows the alpha-3 and numeric forms, so you can convert between the three representations in one step.