SIRET/SIREN Generator
GeneratorGenerate valid French SIREN (9-digit) and SIRET (14-digit) business identification numbers for testing. Implements the official Luhn checksum, including the La Poste mod-5 exception. For testing purposes only.
Need the matching French VAT (TVA) number too?
This tool generates a French SIREN/SIRET. To generate the matching intracommunity VAT (TVA) number for a SIREN, use our TVA Generator →
About this tool
About SIRET/SIREN Generator
SIREN (Système d'Identification du Répertoire des Entreprises) is the 9-digit number INSEE assigns to every French legal entity. SIRET adds a 5-digit NIC (établissement number) to identify a specific physical establishment, for 14 digits total. Both are protected by the Luhn checksum — with one famous exception: La Poste (SIREN 356000000), whose ~13,000 establishments could not all satisfy standard Luhn after a 2010 status change, so most of its SIRETs are instead validated with a simple rule: the sum of all 14 digits must be a multiple of 5.
This generator produces a Luhn-valid 9-digit SIREN, an optional 14-digit SIRET (SIREN + a random 4-digit establishment sequence, with the 14th digit solved so the whole number passes Luhn), or a La Poste example SIRET that satisfies the mod-5 exception. Every number is format-valid for testing but entirely fictitious.
Ideal for testing France-facing business applications: invoicing and accounting software, B2B onboarding and KYB flows, e-commerce checkout fields that collect a SIRET, and any form or test suite that needs realistic French company identifiers without using a real registered business's number.
Generated numbers always pass the correct checksum for their type — standard Luhn for ordinary companies, the mod-5 rule for the La Poste example. Everything runs locally in the browser with no data sent anywhere.
Key Features
- Generate a 9-digit SIREN or a 14-digit SIRET
- Correct Luhn checksum on every generated number
- Includes a La Poste (SIREN 356000000) example exercising the mod-5 exception
- Formatted output (XXX XXX XXX / XXX XXX XXX XXXXX)
- Instant copy to clipboard
- 100% browser-based, no data sent
- For testing purposes only
FAQ
SIRET/SIREN Generator — Frequently Asked Questions
What is the difference between SIREN and SIRET?
SIREN (9 digits) identifies the legal entity — the company itself, once, no matter how many locations it has. SIRET (14 digits) identifies a specific establishment: it is the SIREN plus a 5-digit NIC (établissement number). A company with three offices has one SIREN and three different SIRETs.
Why does La Poste get a different rule?
When La Poste became a public corporation (société anonyme) in 2010, all of its roughly 13,000 individual establishments were consolidated under a single SIREN (356000000). It turned out that not every one of those establishment numbers could be made to satisfy the standard Luhn checksum, so INSEE defined a simpler rule specifically for that SIREN: the sum of all 14 digits of the SIRET must be a multiple of 5. Interestingly, La Poste's own head-office SIRET (356 000 000 00048) does NOT satisfy that mod-5 rule — it is a hardcoded exception that still uses standard Luhn.
Are these generated numbers real companies?
No. The SIREN is a random 8-digit number with a correctly computed Luhn check digit, and the SIRET adds a random establishment sequence with its own correctly computed check digit. They pass the checksum but are not assigned to any real business by INSEE.
Can I generate a SIRET for a specific SIREN?
The generator can build a SIRET on top of any Luhn-valid 9-digit SIREN, including one you already have, by solving for the final NIC digit that makes the full 14-digit number pass the correct checksum.
Tips
- SIREN is always 9 digits; SIRET is always 14 (SIREN + 5-digit NIC)
- Use the La Poste example to see the mod-5 exception in action
- Pair a generated SIREN with the TVA Generator to get a matching French VAT number
- These numbers are for testing only — they are not registered with INSEE
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