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 define internationally recognised codes of letters and/or numbers that we can use when we refer to countries and subdivisions. However, it does not define the names of countries – this information comes from United Nations sources (Terminology Bulletin Country Names and the Country and Region Codes for Statistical Use maintained by the United Nations Statistics Divisions).
Using codes saves time and avoids errors as instead of using a country's name (which will change depending on the language being used) we can use a combination of letters and/or numbers that are understood all over the world.
For example, all national postal organizations throughout the world exchange international mail in containers identified with the relevant country code. Internet domain name systems use the codes to define top level domain names such as '.fr' for France, '.au' for Australia. In addition, in machine readable passports, the codes are used to determine the nationality of the user and when we send money from one bank to another the country codes are a way to identify where the bank is based.
How can I access ISO 3166?
The codes in ISO 3166 are available on the Online Browsing Platform. The information on the OBP is always up to date and you can sign up for notifications to be informed when changes are made by clicking on the follow function in the top right hand corner.
What is included in ISO 3166?
ISO 3166 has three parts: codes for countries, codes for subdivisions and formerly used codes (codes that were once used to describe countries but are no longer in use).
The country codes can be represented either as 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) which can be useful if you need to avoid using Latin script.
The codes for subdivisions are represented as the alpha-2 code for the country, followed by up to three characters. For example ID-RI is the Riau province of Indonesia and NG-RI is the Rivers province in Nigeria. Names and codes for subdivisions are usually taken from relevant official national information sources.
The formerly used codes are four letter codes (alpha-4). How the alpha 4 codes are constructed depends on the reason why the country name has been removed.
Read more about the different types of codes in the Glossary for ISO 3166.
How is ISO 3166 maintained?
ISO 3166 is regularly updated to reflect changes in country names and subdivisions. These changes are done by the ISO 3166 Maintenance Agency (ISO3166/MA).
The maintenance agency includes representatives from the following ten organizations:
- Association française de normalization AFNOR (France)
- American National Standards Institute ANSI (United States)
- British Standards Institution BSI (United Kingdom)
- Deutsches Institut für Normung DIN (Germany)
- Swedish Standards Institute SIS (Sweden)
- International Atomic Energy Agency (IAEA)
- International Telecommunication Union (ITU)
- Internet Corporation for Assigned Names and Numbers (ICANN)
- Universal Postal Union (UPU)
- United Nations Economic Commission for Europe (UNECE)