Country Code Quiz

How this list was compiled: Questions, wrong choices and explanations were written for this site, and every code in them comes from one table of codes read on 2026-10-01. The 193 countries are the member states of the United Nations, https://www.un.org/en/about-us/member-states, read the same day, under the names this site's world capitals quiz uses. Two-letter codes (ISO 3166-1 alpha-2): the table at https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2 and the ISO column of the GeoNames country table, https://download.geonames.org/export/dump/countryInfo.txt; a code is asked only where the two agree, and all 193 do. Where a line says the letters match the country's name in its own language, the Wikipedia table says so and the name was also read in the Unicode CLDR list of country names in that language, https://github.com/unicode-org/cldr-json (German, Spanish, Croatian, Estonian, Dutch, French). Licence: own work

How this list was compiled: Questions, wrong choices and explanations were written for this site, and every code in them comes from one table of codes read on 2026-10-01. The 193 countries are the member states of the United Nations, https://www.un.org/en/about-us/member-states, read the same day, under the names this site's world capitals quiz uses. Internet domains: every domain asked is a delegated country-code top-level domain in the IANA Root Zone Database, https://www.iana.org/domains/root/db; which country it belongs to was read in the GeoNames country table, https://download.geonames.org/export/dump/countryInfo.txt, and in the table at https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2, and the two agree for all 193. The United Kingdom's domain is .uk and its ISO code is GB. Licence: own work

How this list was compiled: Questions, wrong choices and explanations were written for this site, and every code in them comes from one table of codes read on 2026-10-01. The 193 countries are the member states of the United Nations, https://www.un.org/en/about-us/member-states, read the same day, under the names this site's world capitals quiz uses. Calling codes: the International Telecommunication Union's List of Recommendation ITU-T E.164 assigned country codes (position on 15 December 2016, the Annex to its Operational Bulletin 1114), https://www.itu.int/dms_pub/itu-t/opb/sp/T-SP-E.164D-2016-PDF-E.pdf, and the phone column of the GeoNames country table, https://download.geonames.org/export/dump/countryInfo.txt; a code is asked only where the two agree. The list at https://en.wikipedia.org/wiki/List_of_telephone_country_codes was read as well. Licence: own work