Though GB is the United Kingdom's ISO 3166-1 alpha-2 code, UK is exceptionally reserved for the United Kingdom on the request of the country (United Kingdom). Its main usage is the .uk internet country code top-level domain (ccTLD) and, on 28 September 2021, UK replaced GB as the official country code on motor vehicle registration plates .

The sortable table below contains the three sets of ISO 3166-1 country codes for each of its 249 countries, links to the ISO 3166-2 country subdivision codes, and the Internet country code top-level domains (ccTLD) which are based on the ISO 3166-1 alpha-2 standard with the few exceptions noted.

ISO 3166 is an international standard which defines codes representing names of countries and their subdivisions. The standard specifies basic guidelines for the implementation and maintenance of country and subdivisions codes. Most people refer to ISO 3166, but actually it is divided into three parts.

ISO 3166-1 (Codes for the representation of names of countries and their subdivisions – Part 1: Country code) is a standard defining codes for the names of countries, dependent territories, and special areas of geographical interest. It is the first part of the ISO 3166 standard published by the International Organization for Standardization.

ISO 3166-2:GB is an International Organization for Standardization (ISO) coding system that gives geocodes to administrative divisions of the United Kingdom: The Channel Islands and the Isle of Man are not part of the UK, but ISO offers codes for them under "GB-". The first part of each code is the ISO 3166-1 code GB for the United Kingdom.

This is a complete list of all country ISO codes as described in the ISO 3166 international standard. These codes are used throughout the IT industry by computer systems and software to ease the identification of country names.

The International Organization for Standardization defines its country codes in standard 3166-1. ISO codes also consist of three capital letters in the alpha-3 version. For example, Germany has the IOC code "GER" for the English country name "Germany."

Aug 9, 2022 · You should use 2-letter ISO 3166-1 alpha-2 codes. For the UK, use the following extended codes: GB-ENG for England; GB-NIR for Northern Ireland; GB-SCT for Scotland; GB-WLS or GB-CYM for Wales

This identifier enables anyone creating datasets to accurately and consistently link data to a constituent part of the United Kingdom. It makes it easier for anyone using the data to join it with other datasets and and map it to a known geographical extent.

The purpose of ISO 3166-2 is to establish an international standard of short and unique alphanumeric codes to represent the relevant administrative divisions and dependent territories of all countries in a more convenient and less ambiguous form than their full names.