ISO Standard Codes Complete Reference (2026 Edition)
In the world of global software development, standardization is the key to interoperability. Whether you are building an e-commerce platform, a localization tool, or a global data warehouse, you will inevitably encounter ISO codes. This guide provides a complete reference to the three most important ISO standards for developers: ISO 639 (Languages), ISO 3166 (Countries), and ISO 4217 (Currencies).
Quick Search
You can use Ctrl + F (or Cmd + F on Mac) to quickly find a specific code or name in the tables below.
1. ISO 639: Language Codes
ISO 639 is a set of international standards for language codes. The most commonly used is ISO 639-1 (two-letter codes).
| Code | Language Name | Native Name |
|---|---|---|
| en | English | English |
| zh | Chinese | 中文 |
| es | Spanish | Español |
| fr | French | Français |
| de | German | Deutsch |
| ja | Japanese | 日本語 |
| ko | Korean | 한국어 |
| pt | Portuguese | Português |
| ru | Russian | Русский |
| ar | Arabic | العربية |
2. ISO 3166: Country & Territory Codes
ISO 3166-1 Alpha-2 codes are the most widely used standards for representing countries and territories.
| Code | Country Name | Region |
|---|---|---|
| US | United States | Americas |
| CN | China | Asia |
| DE | Germany | Europe |
| FR | France | Europe |
| JP | Japan | Asia |
| GB | United Kingdom | Europe |
| BR | Brazil | Americas |
| IN | India | Asia |
| CA | Canada | Americas |
| AU | Australia | Oceania |
3. ISO 4217: Currency Codes
ISO 4217 is the international standard for currency codes.
| Code | Currency Name | Symbol |
|---|---|---|
| USD | US Dollar | $ |
| EUR | Euro | € |
| JPY | Japanese Yen | ¥ |
| GBP | British Pound | £ |
| CNY | Chinese Yuan | ¥ |
| AUD | Australian Dollar | $ |
| CAD | Canadian Dollar | $ |
| CHF | Swiss Franc | CHF |
| HKD | Hong Kong Dollar | $ |
| INR | Indian Rupee | ₹ |
Use Cases and Best Practices
Localization (i18n)
When combining ISO 639 and ISO 3166, you get Locale Tags (e.g., en-US, zh-CN). These are used to tell the browser or application which language and regional format (date, currency, etc.) to use.
Data Normalization
Always use ISO codes in your database instead of full country names. Country names can vary (e.g., "USA" vs "United States of America"), but "US" is a universal constant.
Financial Transactions
ISO 4217 codes are mandatory for any financial integration (Stripe, PayPal, SWIFT). They ensure that an amount is processed in the correct currency regardless of the display symbol.
FAQ
Q: What is the difference between ISO 639-1 and ISO 639-2?
A: ISO 639-1 uses 2-letter codes (e.g., en), while ISO 639-2 uses 3-letter codes (e.g., eng). 639-1 is preferred for most web applications.
Q: Are ISO codes case-sensitive?
A: Generally, ISO 639 language codes are lowercase (en) and ISO 3166 country codes are uppercase (US). However, most applications should handle them case-insensitively for safety.
Q: Is "UK" a valid ISO 3166 code?
A: No, the valid ISO code for the United Kingdom is GB. "UK" is reserved but not the official code in the standard.
Related Tools
- Unit Converter - For measurement conversions.
- JSON Formatter - To format your configuration files containing these codes.