What is a VAT Number and Why Validate It?
A complete guide to VAT registration numbers, EU format rules, VIES lookup, and why businesses must verify their trading partners' VAT numbers.
What is a VAT number?
A Value Added Tax (VAT) number — also called a VAT registration number or VAT ID — is a unique identifier assigned by a national tax authority to a business that is registered to collect and remit VAT. In the European Union, these numbers follow a standardised format defined by the EU VAT Directive, and are valid across all 27 member states.
VAT is a consumption tax applied at each stage of the supply chain. Businesses registered for VAT charge it on their sales and can reclaim it on their purchases (input tax). To trade cross-border within the EU without charging VAT (zero-rating), both the seller and buyer typically need to be VAT-registered.
Why do businesses need to validate VAT numbers?
Validating a trading partner's VAT number is important for several reasons:
- Legal compliance: EU VAT law requires sellers to verify the buyer's VAT number before zero-rating a B2B transaction. If the number turns out to be invalid, you may be liable for the uncollected VAT.
- Fraud prevention: Fraudsters sometimes provide fake VAT numbers to avoid paying VAT on purchases. Validation prevents this.
- Invoice accuracy: Invoices must include the buyer's and seller's VAT numbers for intra-EU supplies. Incorrect numbers can invalidate the invoice.
- Audit trails: Tax authorities expect businesses to demonstrate due diligence. A validation record (with timestamp) provides evidence of good faith.
Format validation vs. VIES lookup
There are two levels of VAT number checking:
- Format validation checks that the number has the correct structure for its country: the right prefix, length, and checksum (where applicable). This is fast and free — it works offline. However, a number that passes format checks is not necessarily active.
- VIES lookup (VAT Information Exchange System) queries the EU's live registry to confirm that the number is currently registered and active. This requires a live API call to the EU VIES service and may return name and address information for the registered business.
For most compliance purposes, format + VIES validation is sufficient. The VIES service is operated by the European Commission and covers all 27 EU member states.
VAT number formats by country
Each EU country has its own VAT format. Here are the most common ones:
| Country | Prefix | Format | Example |
|---|---|---|---|
| Germany | DE | 9 digits | DE129273398 |
| France | FR | 2 chars + 9 digits | FR40303265045 |
| Netherlands | NL | 9 digits + B + 2 digits | NL123456789B01 |
| Spain | ES | letter/digit + 7 digits + letter/digit | ESA12345674 |
| Italy | IT | 11 digits | IT12345678901 |
| Poland | PL | 10 digits | PL1234567890 |
| Sweden | SE | 10 digits + 01 | SE123456789001 |
| United Kingdom | GB | 9 digits | GB980780684 |
How to use Versys for VAT validation
Versys supports format validation for all EU and EEA member states plus the United Kingdom, entirely free and without an account. For live VIES lookups — which confirm a number is currently registered — you'll need a free Versys account (VIES lookups consume credits, which are granted monthly for free).
You can also validate VAT numbers via the Versys API, which supports both single checks and batch validation of up to 100 numbers in one request.
Validate a VAT number now
Free format check for any EU or UK VAT number. No account needed.
Open Versys VAT CheckerBrowse VAT number examples by country
Our VAT Number Directory lists canonical VAT numbers for all 27 EU member states and the UK, each with a full format validation report and live VIES registration lookup.
If you want the practical workflow for onboarding and invoicing, see our EU VAT checks guide.