🇫🇷 French Social Security Number (NIR) Validator
Check the key of a French social security number (NIR), decode the sex, month and year of birth and place of birth it contains, or calculate the key from the first 13 characters. Everything runs locally in your browser.
15 characters to validate a full number, or 13 characters to calculate the 2-digit key. Spaces are optional; Corsica (2A/2B) is supported.
ℹ️ This tool checks the structure and key of a number. It does not confirm that the number is registered with the INSEE or the Assurance Maladie. A social security number is personal data: avoid sharing it unnecessarily.
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About the French NIR Validator
The NIR (Numéro d'Inscription au Répertoire), commonly called the numéro de sécurité sociale, is the 15-character identifier assigned by the INSEE to every person born or registered in France. Its last two digits are a key that detects typing errors.
This tool verifies that key, handles the special cases (Corsica, overseas departments, people born abroad, temporary numbers) and explains what each part of the number means.
Key Features
- Key validation: key = 97 − (first 13 digits modulo 97).
- Corsica support: 2A and 2B are replaced by 19 and 18 for the calculation, as required.
- Decoding: sex, month and year of birth, department or country of birth, INSEE code and order number.
- Key calculator: enter the first 13 characters to get the missing key.
How to Use the Tool
- Step 1: Type or paste the number, with or without spaces.
- Step 2: Click Check.
- Step 3: With 15 characters, the tool validates the key; with 13, it calculates it.
- Step 4: Copy the formatted number with the 📋 button.
Structure of a NIR
| Position | Meaning | Example |
|---|---|---|
| 1 | Sex: 1 man, 2 woman (7/8 temporary number) | 2 |
| 2–3 | Year of birth (2 digits) | 69 |
| 4–5 | Month of birth | 05 |
| 6–7 | Department of birth (2A/2B, 97x, or 99 if born abroad) | 49 |
| 8–10 | INSEE commune code (or country code) | 588 |
| 11–13 | Birth order number in the commune that month | 157 |
| 14–15 | Key | 80 |
Common Use Cases
- Checking a number before filling in an HR, payroll or health form
- Implementing and testing NIR validation in business software
- Finding a forgotten key from the first 13 digits
- Understanding what a social security number reveals
Tips & Best Practices
- The year has only two digits: the tool shows both centuries when both are possible.
- For people born before 1968, codes 75, 78 and 91–95 can refer to former departments.
- Under the GDPR and the French "décret NIR", collecting this number is restricted to specific purposes (payroll, health, social security).
Privacy & Security
The check runs entirely in your browser with JavaScript. The number you enter is never sent to a server, stored or logged, and the page keeps no history.