France / Company numbers
SIRET and SIREN Validator (France)
Check French SIREN (9-digit company) and SIRET (14-digit establishment) numbers and their check digits, and get the French VAT number from a SIREN. Checks a list at once.
SIRET and SIREN Validator (France): A SIREN identifies a company; a SIRET adds a five-digit number (NIC) for each establishment, so one SIREN can have many SIRETs. Both end in a Luhn check digit, except the branches of La Poste, which all share one SIREN and use a digit sum divisible by 5. The VAT number is FR, a two-digit key, and the SIREN. Results agreed with the python-stdnum library on 6,000 numbers each. Runs 100% locally in your browser with zero server file uploads.
- Category
- Business & admin tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Both use the Luhn check: every second digit from the right is doubled, and the total must divide by 10. The branches of La Poste, which share one SIREN, use a digit sum divisible by 5 instead. For a valid SIREN the French VAT number is shown too. Only the format is checked, not whether the company is registered; everything stays in your browser.
A worked example
For 12345678, double every second digit from the right, starting with the 8: 16, 12, 8, and 4, written as 7, 3, 8, and 4 once 9 is taken from those over 9. With the undoubled 7, 5, 3, and 1, the total is 38, so the check digit is 2 and the SIREN is 123 456 782.
For other countries, see the NIF validator for Portugal and the DNI and NIE validator for Spain.
SIREN or SIRET?
The SIREN stays the same for the life of a company; the SIRET changes when it moves, because each address is a new establishment. Use the SIREN to identify the company and the SIRET for one site, for example on a payslip.
How to use it
- Type or paste SIREN or SIRET numbers, one per line, with or without spaces.
- Read which are valid and, for a SIREN, its intra-EU VAT number.
- For a SIRET that fails, see whether the SIREN in it or the whole number is wrong.
Privacy & limitations
Numbers are checked in your browser and never sent anywhere.
Related tools
Frequently asked questions
Does a valid result mean the company exists?
No: only that the number is correctly formed. Look a company up in the public Sirene directory (annuaire-entreprises.data.gouv.fr) to confirm it is registered and active.
How is the VAT number made from the SIREN?
The key is (12 + 3 × (SIREN mod 97)) mod 97, written with two digits, so 123 456 782 gives FR 11 123456782.
Which number goes on an invoice?
French invoices show the SIREN or SIRET and, for VAT-registered businesses, the intra-EU VAT number.
Free tool · runs in your browser · no account required