An ISO 3166-1 country code validator checks whether a country code is valid according to the international standard. Enter an alpha-2 (2-letter), alpha-3 (3-letter), or numeric (3-digit) code to validate it, or search by country name to find the correct codes.
Country Details
Validation Checks
ISO 3166-1 Reference (249 Countries)
| Country | Alpha-2 | Alpha-3 | Numeric | Region |
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How to Use the Country Code Validator
ISO 3166-1 country codes are used everywhere — in international shipping, financial transactions, HTML language attributes, DNS country-code TLDs, and phone number prefixes. This country code validator supports all three ISO 3166-1 formats and includes reverse lookup by country name.
Step 1: Enter a Code or Country Name
The input field accepts any of the three ISO 3166-1 formats: alpha-2 (2 letters, e.g., DE), alpha-3 (3 letters, e.g., DEU), or numeric (3 digits, e.g., 276). You can also type the country's English name for reverse lookup — partial matching works, so "korea" will find both "Korea, Republic of" and "Korea (Democratic People's Republic of)."
Step 2: Review the Validation Result
If the code is valid, the tool shows all three format equivalents plus additional details: the official country name, geographic region, phone prefix, and internet TLD. This makes it easy to switch between code formats without needing to look them up separately. The validation checklist confirms which format was detected.
Understanding ISO 3166-1 Format Differences
Alpha-2 codes (2-letter) are the most widely used — you see them in HTML lang attributes (lang="en-US"), country-code TLDs (.us, .de, .jp), and ISO 4217 currency codes often follow the same country prefix. Alpha-3 codes (3-letter) appear in machine-readable passports (MRZ zones) and UN/government databases where 2-letter codes are ambiguous. Numeric codes are used in systems that cannot handle letters, such as certain mainframe databases and some international banking standards.
Historical and Deprecated Codes
ISO 3166-1 also maintains historical records of codes for countries that no longer exist or have been renamed. For example, CS was used for Czechoslovakia (until 1993) and then briefly for Serbia and Montenegro (until 2006). Entering a deprecated code will show what country it referred to and when it was deprecated. This is useful when cleaning up older datasets that contain obsolete country codes.
FAQ
What are ISO 3166-1 country codes?
ISO 3166-1 is the international standard defining codes for countries and territories. It defines three formats: alpha-2 (2-letter, like US, GB, DE), alpha-3 (3-letter, like USA, GBR, DEU), and numeric (3-digit, like 840, 826, 276). Alpha-2 codes are the most commonly used, appearing in domain extensions (.us, .gb) and HTML lang attributes.
What is the difference between alpha-2 and alpha-3 codes?
Alpha-2 codes are 2-letter abbreviations (e.g., US for United States, DE for Germany). Alpha-3 codes are 3-letter codes (e.g., USA, DEU) that allow better distinction between similar countries. Alpha-3 is used in passports and financial systems. Numeric codes are used in databases where alphanumeric codes could conflict.
Is my data private?
Yes, all validation runs entirely in your browser using an embedded ISO 3166-1 lookup table. No data is sent to any server.
Does this include territories and dependent areas?
Yes, the tool includes all 249 entries in ISO 3166-1, including dependent territories, autonomous regions, and special administrative areas. You can also use it to look up historical/deprecated codes and see what country they previously referred to.
Why is my country code showing as deprecated?
ISO 3166-1 maintains codes for dissolved countries and renamed territories as historical codes. Examples include CS (formerly Czechoslovakia/Serbia and Montenegro), AN (Netherlands Antilles), and YU (Yugoslavia). These codes are no longer officially assigned but may appear in older data.
Can I search by country name?
Yes, this tool supports reverse lookup — type a country name in the search field and it will find the corresponding ISO codes. Partial name matching is supported (e.g., typing 'korea' will find both South Korea and North Korea).