A SIREN is the 9-digit number that uniquely identifies a French legal entity in the national business register (Répertoire des Entreprises), maintained by INSEE. It is the root identifier behind every SIRET, VAT number and Kbis extract. This free validator runs the official Luhn check in your browser so you can confirm a supplier or partner number is well-formed before trusting it.
How it works
The SIREN uses the Luhn (mod-10) algorithm over all 9 digits:
- Strip spaces; you must have exactly 9 digits.
- Starting from the rightmost digit and moving left, double every second digit.
- If a doubled value exceeds 9, subtract 9.
- Sum all the resulting values.
- The SIREN is valid if that sum is divisible by 10.
The same digits then form the prefix of the company’s 14-digit SIRET codes and are used to derive the French VAT number’s check key.
Example
Check 732 829 320 → digits 7 3 2 8 2 9 3 2 0.
Working from the right, double the 2nd, 4th, 6th and 8th digits (subtracting 9 where the result exceeds 9), then add everything together. If the Luhn total is divisible by 10, the SIREN passes.
Notes
A valid checksum tells you the number is internally consistent, not that the company is currently registered or trading. To confirm legal status, look the SIREN up in the INSEE Sirene database or on Infogreffe. All processing here happens locally — your SIREN never leaves your browser.