ISO 3166-1 numeric (or numeric-3) codes are three-digit country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), to represent countries, dependent territories, and special areas of geographical interest. They are similar to the three-digit country codes developed and maintained by the United Nations Statistics Division, from which they originate in its UN M.49 standard. They were first included as part of the ISO 3166 standard in its second edition in 1981, but they were released by the United Nations Statistics Division since as early as 1970.^[1]

An advantage of numeric codes over alphabetic codes is script (writing system) independence.^[2] The ISO 3166-1 alphabetic codes (alpha-2 and alpha-3) use letters from the 26-letter English alphabet and are suitable for languages based on the Latin alphabet. For people and systems using non-Latin scripts (such as Arabic or Japanese), the English alphabet may be unavailable or difficult to use, understand, or correctly interpret. While numeric codes overcome the problems of script dependence, this independence comes at the cost of loss of mnemonic convenience.

Another advantage is that when countries merge or split, they will get a new numeric code, while the alphabetic code stays in use for (a part of) that country. A persistent number is needed in datasets with historical country information.

When countries merge, split, or undergo territorial change, their numeric codes are withdrawn and new numeric codes are assigned. For example:

• East Germany and West Germany used numeric codes 278 and 280 respectively before their unification in 1990. Since then, the unified Germany has used numeric code 276, while keeping the alphabetic codes for West Germany (except in the banking area where they still use the 280 code^[5]).
• Ethiopia used numeric code 230 before Eritrea split away in 1993. Since then, Ethiopia has used numeric code 231, while keeping the same alphabetic codes.
• Sudan used numeric code 736 before South Sudan split away in 2011. Since then, Sudan has used numeric code 729, while keeping the same alphabetic codes.

If a country changes its name without any territorial change, its numeric code remains the same. For example, when Burma was renamed Myanmar without territorial change in 1989, its alphabetic codes were changed, but its numeric code 104 has remained the same.

The following numeric codes have been withdrawn from ISO 3166-1:^[6]

The following numeric codes were also assigned by the United Nations Statistics Division, but these territories were never officially included in ISO 3166-1:^[1]

In the UN M.49 standard developed by the United Nations Statistics Division, additional numeric codes are used to represent geographical regions and groupings of countries and areas for statistical processing purposes, but these codes are not included in ISO 3166-1. Unlike alphabetic codes, there are no reserved numeric codes in ISO 3166-1.