The formula of the key, step by step
The key is (12 + 3 × (SIREN modulo 97)) modulo 97, written with two digits. Here is the calculation for Danone, whose SIREN is 552 032 534:
| Step | Calculation | Result for Danone |
|---|---|---|
| 1 | Remainder of the SIREN divided by 97 | 552032534 modulo 97 = 5 |
| 2 | Multiply by 3 | 5 × 3 = 15 |
| 3 | Add 12 | 15 + 12 = 27 |
| 4 | Remainder of the division by 97: the key | 27 modulo 97 = 27 |
| 5 | Write FR, the two-digit key, then the SIREN | FR27552032534 |
The Excel formula
With the SIREN in column A, formatted as text, this formula returns the full VAT number:
="FR"&TEXT(MOD(12+3*MOD(A2,97),97),"00")&A2
For a 14-digit SIRET, take its first 9 digits first with =LEFT(A2,9): the key is always computed on the SIREN. More formulas in checking SIREN, SIRET and VAT numbers in Excel.
What the calculation does not tell you
The calculation gives the number the company would have if it is registered for VAT. It does not tell you:
- whether the company is really registered: a micro-business under the VAT exemption often has no valid number;
- whether the company is still active;
- whether the SIREN you started from is right. A typo in the SIREN gives a well-formed number, but another company's, or nobody's.
Check the number you get
Enter the SIREN or the computed number in the tool at the top of this page: it redoes the calculation and asks the administration's service whether the number is valid. For a refused number, see what to do with an invalid VAT number. The full format is explained in the French VAT number.
Frequently asked questions
How do I calculate the VAT key of a SIREN?+
Take the remainder of the SIREN divided by 97, multiply it by 3, add 12, then take the remainder of the division by 97. The result, written with two digits, is the key.
Can I calculate the VAT number from a SIRET?+
Yes, by keeping only the first 9 digits of the SIRET, which are the SIREN. The VAT number is the same for every site of the company.
Is a computed VAT number valid?+
Not always. The company must be registered for VAT: a micro-business under the exemption often has no valid number. Always check the number you get.
What is Danone's VAT number?+
FR27552032534: FR, the key 27, then the SIREN 552 032 534.
Keep reading
- VATFrench VAT number: format and how to check itThe French, Belgian and Swiss formats, the mentions on the invoice and the check before invoicing.
- VATVAT number examples in each European countryThe prefix, the length and an example for each country of the European Union, Switzerland, Norway and the United Kingdom.
- VATInvalid, unverifiable or unregistered VAT number: what to doWrong number, service unavailable or number not registered: the effect on the VAT exemption and what to do.
- EXCELBulk check SIREN, SIRET and VAT numbers in ExcelPrepare the column, spot errors with formulas, then check every row: the method for a whole workbook.
- SIRENWhat is a SIREN number and how to find itThe 9-digit format, who gets one, where it appears and how to find a company's SIREN from its name.
Check a VAT number
Type the number with its country code (FR, DE, IT, ES...).
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