France SIREN / SIRET Validator
Check a French SIREN (9-digit company) or SIRET (14-digit establishment) number with the Luhn checksum. 100% local. Built for France.
Batch check — paste many, one per line
Validate a French SIREN or SIRET
Enter a 9-digit SIREN or 14-digit SIRET to verify its Luhn checksum. Spaces are ignored. Everything runs locally in your browser.
In France, SIREN (9 digits) identifies a legal entity and SIRET (14 digits = SIREN + 5-digit NIC) identifies each establishment; both are assigned by INSEE. Standard validation is the Luhn algorithm: doubling every second digit from the right and requiring the total to be a multiple of 10. This tool applies Luhn to SIREN and SIRET, splits a SIRET into its SIREN and NIC parts, and explains failures — all locally in your browser.
Known edge case: establishments of La Poste (SIREN 356 000 000) are the official exception — their SIRETs follow a different internal rule (sum of digits divisible by 5) and can fail plain Luhn; treat those separately. Structural validity does not mean the company is active: check the free public registries (sirene.fr / annuaire-entreprises.data.gouv.fr) for live status, name and address. Last verified: July 2026.
FAQ
What is the difference between SIREN, SIRET and NIC?
SIREN (9 digits) = the company. NIC (5 digits) = one specific establishment of that company. SIRET = SIREN + NIC (14 digits). A company moving offices keeps its SIREN but gets a new NIC/SIRET.
How does the Luhn check work here?
From the rightmost digit, double every second digit; if doubling gives more than 9, subtract 9. Sum everything: a valid SIREN/SIRET totals a multiple of 10. It reliably catches single typos and most digit swaps.
Why does a La Poste SIRET fail this check?
La Poste (SIREN 356 000 000) is the documented exception: its establishment numbers satisfy "sum of all 14 digits divisible by 5" instead of Luhn. If you handle postal-service SIRETs, validate them under that special rule.
How do I confirm a company is real and active?
Look it up in the public Sirene database (sirene.fr or annuaire-entreprises.data.gouv.fr) — free and authoritative for status, legal form and address. This tool is the instant offline pre-check.