🇫🇷 SIRET & SIREN Validator
Check the key of a French SIREN (company) or SIRET (establishment) number, get the matching EU VAT number and calculate a missing check digit. Everything runs locally in your browser.
9 digits (SIREN) or 14 digits (SIRET). Enter 8 or 13 digits to calculate the last one. Spaces are optional.
ℹ️ This tool checks the check digit only; nothing is sent anywhere. To know whether a company exists or is still active, open the official directory with the link shown in the result (annuaire-entreprises.data.gouv.fr).
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About the SIRET & SIREN Validator
In France, every company receives a 9-digit SIREN number from the INSEE, and each of its establishments a 14-digit SIRET number (SIREN + 5-digit NIC). Both end with a check digit calculated with the Luhn algorithm, which this tool verifies.
It also handles the well-known exception of La Poste, whose thousands of establishments share one SIREN and use a different rule, and derives the intra-EU VAT number from the SIREN.
Key Features
- SIREN and SIRET: automatic detection from the number of digits.
- La Poste exception: establishments of SIREN 356 000 000 are checked with the sum-of-digits rule.
- VAT number: FR + 2-digit key + SIREN, calculated instantly.
- Check digit calculator: enter 8 or 13 digits to get the missing last digit.
How to Use the Tool
- Step 1: Paste a SIREN or SIRET, with or without spaces.
- Step 2: Click Validate.
- Step 3: Read the SIREN, NIC and VAT number.
- Step 4: Follow the link to the official company directory to check the company's status.
Structure
| Number | Digits | Content |
|---|---|---|
| SIREN | 9 | 8 digits + Luhn check digit |
| NIC | 5 | Establishment number, last digit makes the SIRET pass the Luhn check |
| SIRET | 14 | SIREN + NIC |
| VAT | 13 chars | FR + key [(12 + 3 × (SIREN mod 97)) mod 97] + SIREN |
Common Use Cases
- Checking a supplier's SIRET on an invoice or a quote
- Validating company data in a signup form or a CRM
- Finding the VAT number of a French company from its SIREN
- Detecting typos in bulk imports of company data
Tips & Best Practices
- A company keeps its SIREN for life, but gets a new SIRET each time it opens or moves an establishment.
- Store these numbers as text to keep leading zeros.
- The VAT number computed from a SIREN is the theoretical one; check VIES before applying the reverse charge.
Privacy & Security
The check runs entirely in your browser. The number is only sent to the official directory if you click the link yourself.