Reference
Markdown exportVAT ID
Tax identifier used for VAT reporting and cross-border trade in the EU.
Definition
Tax identifier used for VAT reporting and cross-border trade in the EU.
Why this term matters
A valid VAT ID is what enables intra-EU reverse-charge under Article 138 of the VAT Directive and what tax authorities cross-check against VIES. Sending an invalid or unverified VAT ID on a cross-border B2B invoice exposes the supplier to retroactive VAT charges plus penalties, even when the buyer is genuinely VAT-registered.
Explanation
Often required in B2B e-invoices and for reverse-charge scenarios.
May be used as part of PEPPOL Participant IDs (scheme-dependent).
Common mistakes
Use these points as the practical checks for this section.
- Confusing the VAT ID (BT-31, e.g., DE123456789) with the local tax registration number (BT-32) or the company registration number (BT-30).
- Failing to prefix the country code — VIES rejects "123456789" but accepts "DE123456789".
- Storing the VAT ID without VIES verification, then issuing a reverse-charge invoice to a buyer whose VAT ID was deregistered last quarter.
- Putting a personal/seller-only tax ID into the buyer VAT ID field on B2C invoices — the VAT ID elements should simply be omitted for unidentified consumers.
Frequently asked questions
How do I verify a VAT ID?
Use the EU VIES service (ec.europa.eu/taxation_customs/vies) which exposes a SOAP and REST API. Most ERPs and invoicing platforms can call it on every new customer record and store the verification timestamp for audit purposes.
Where does the VAT ID go in EN 16931?
Seller VAT ID is BT-31 (cac:PartyTaxScheme/cbc:CompanyID with schemeID="VAT" in UBL). Buyer VAT ID is BT-48. The country code prefix is part of the value, not a separate attribute.
Is the VAT ID always required on a B2B invoice?
For domestic B2B with reverse charge or for any intra-EU B2B supply where VAT is shifted to the buyer, yes. For pure domestic B2B without reverse charge, jurisdictions like Germany require it for invoices above €250 (§14 UStG); below that threshold the small-invoice rules apply.