ISO Country Codes Explained
Three identifiers for the same country
ISO 3166-1 gives every country three identifiers: a two-letter alpha-2 code, a three-letter alpha-3 code, and a three-digit numeric code. Japan is JP, JPN, and 392; Brazil is BR, BRA, and 076.
The alpha-2 code is the most compact and is used for ccTLDs, shipping labels, and language-region tags. Alpha-3 codes are more readable and appear on machine-readable passports and in United Nations datasets.
Where the numeric code matters
The numeric code was designed for systems that cannot reliably handle Latin letters, such as older financial, statistical, or transportation databases. It remains stable even when a country changes its name or official designation.
Because the numeric code is assigned once, it is useful for joining records across systems that use different language names for the same territory.
Notable exceptions
Some codes do not match the obvious name. The United Kingdom is GB rather than UK, Germany is DE from its German name Deutschland, and Switzerland is CH from Confoederatio Helvetica.
When you search an alias such as UK or Germany here, the result resolves to the correct ISO record and shows the official codes.