How country code lookup works
ISO 3166-1 is the international standard that assigns every country — and quite a few territories — three interchangeable code elements: a two-letter alpha-2 (GB), a three-letter alpha-3 (GBR) and a three-digit numeric (826). This tool resolves all three directions: type any of the codes, or part of a country name, and get the full identity. DE, DEU and 276 are all Germany. The alpha-2 codes are the ones you meet daily: internet domains (.uk, .de), locale tags like en-GB, and the country fields in payment and shipping forms.
Lookups are forgiving. Codes match case-insensitively (gb, De and dEu all work); numeric codes work with or without leading zeros (76 and 076 are both Barbados); and name search handles the informal spellings ISO does not assign — UK resolves to GB with a note, USA finds the United States, and Holland, Burma, Swaziland and Czech Republic all map to their current official entries. Partial names search the whole 249-entry table and list matches alphabetically, exact matches first.
The table includes all 249 officially assigned entries — not just UN member states — so you also get Antarctica (AQ), overseas territories (GF for French Guiana, CW for Curaçao) and special entries like the Holy See (VA). Names follow the ISO short-name convention (Korea, Republic of; Taiwan, Province of China), which is why some look formal or surprising; the informal names still resolve through the built-in alias list. This is the same code space your browser, bank and courier software use, so a code that is not in this table will not be in their drop-downs either.