OnSubmitSteps
- Choose generation from SIREN/SIRET or VAT validation.
- Paste one company identifier per line for batch conversion.
- Review any invalid SIREN or SIRET values.
- Copy the generated French VAT numbers.
Finance · free tool
French VAT number checker and SIREN converter
Generate a French VAT number from a valid SIREN or SIRET, then check its local format and key.
Parameters and result
Choose an action
Paste up to 50 valid identifiers. A SIRET is automatically reduced to its 9-digit SIREN.
Local format and key check. Use VIES to confirm that a company is registered for intra-EU trade.
Open the official VIES checkerUse it well
How to use French VAT Generator & Validator
Common use cases
- SIREN to VAT
- Calculate the numeric key and build a French VAT number from a valid SIREN.
- SIRET to VAT
- Extract the first nine digits of a SIRET and generate the same company VAT number.
- Batch CRM preparation
- Convert up to 50 identifiers and flag values with invalid length or Luhn checksum.
- Invoice QA
- Check the FR prefix, VAT key and SIREN before using a value in a test invoice.
Limits and good practices
Good practices
- Store SIREN, SIRET and VAT numbers as strings.
- Distinguish a locally calculated key from official VAT registration.
- Keep the FR country prefix in invoices and exports.
- Check VIES when an intra-EU transaction requires registration evidence.
Common mistakes
- Using all 14 SIRET digits
- A French VAT number uses the nine-digit SIREN, not the complete SIRET.
- Treating a calculation as registration proof
- A coherent key does not prove that the business exists or is enabled for intra-EU trade.
- Dropping the FR prefix
- The complete French VAT identifier starts with FR, followed by the key and SIREN.
FAQ
Frequently asked questions
How do I generate a French VAT number from a SIREN?
Enter the nine-digit SIREN. The tool checks its Luhn checksum, calculates the numeric VAT key and combines FR, the key and the SIREN.
Can a SIRET be converted to a French VAT number?
Yes. The first nine digits of a SIRET are the SIREN used to calculate the company’s French VAT number.
What is the format of a French VAT number?
The common format has 13 characters: FR, a two-digit computer key and the company’s nine-digit SIREN.
Does a generated VAT number prove VAT registration?
No. It proves only local mathematical consistency. The French tax administration assigns VAT numbers and VIES reports intra-EU registration status.
Does this tool query VIES?
No. All calculations run locally in the browser. Use the European Commission’s VIES checker for official intra-EU status.
Can I convert several SIREN or SIRET values at once?
Yes. Paste one identifier per line to convert up to 50 values in one batch.
Why is a SIREN or SIRET rejected?
The tool rejects identifiers with the wrong length, an invalid Luhn checksum or an invalid extracted SIREN.
Are my inputs sent to a server?
OnSubmit tools run in the browser whenever the task can be processed locally. Avoid pasting production secrets, real banking details or personal data into public tools.