What is ISO 3166?
ISO 3166 is the International Standard for country codes and codes for their subdivisions. The purpose of ISO 3166 is to establish internationally recognised codes for the representation of names of countries, territories or areas of geographical interest, and their subdivisions. However, ISO 3166 does not establish the names of countries, only the codes that represent them.
The country names in ISO 3166 come from United Nations sources. New names and codes are added automatically when the United Nations publishes new names in either the Terminology Bulletin Country Names or in the Country and Region Codes for Statistical Use maintained by the United Nations Statistics Divisions. Names for subdivisions are taken from relevant official national information sources.
ISO 3166 was first published in 1974 as a single standard to establish the country codes. It was expanded into three parts in 1997 to include the codes for subdivisions and the codes for names of countries that are no longer in use. Of the three parts, Part 1, ISO 3166-1 is generally used the most often.
Who uses ISO 3166-1?
ISO 3166-1 has become one of the world’s most well known and widely used standards for coding country names. Using a code of letters and/or numbers to represent a country name can help save time and energy, and reduce the rate of error.
The country codes found in ISO 3166-1 are used by many organizations, businesses and governments. For example all national postal organizations throughout the world exchange international mail in containers bearing its country code for identification. In machine readable passports, the codes from ISO 3166-1 are used to determine the nationality of the user. In addition, internet domain name systems use the codes to define top level domain names such as 'fr' for France, 'au' for Australia and 'br' for Brazil.
How to use ISO 3166-1?
ISO 3166-1:2006, Codes for the representation of names of countries and their subdivisions – Part 1: Country codes is the most recent version of the standard.
Within the standard, names of countries are represented by a two-letter code (alpha-2) which is recommended as the general purpose code, a three-letter code (alpha-3) which is more closely related to the country name, and a three digit numeric code (numeric-3 - developed and assigned by the UN Statistics Division) which can be useful when codes need to be understood in countries that do not use Latin scripts.
ISO provides the alpha-2 country codes for free. The full standard containing the alpha-2, alpha-3 and numeric-3 codes as well as details of the administrative language can be purchased. (See table at top right - Resources for ISO 3166-1:2006.)