Business glossary
VAT number
A tax identifier assigned to a business registered for value-added tax.
Example
A VAT-registered supplier uses its assigned VAT identifier on documents where required. A customer may need the identifier to verify the supplier and reconcile a tax invoice.
How it differs from related terms
A VAT number is a tax registration identifier, not a universal business-registration or invoice number. Format, validation and required invoice fields depend on the jurisdiction; an example from one country should not be applied worldwide.
Find and verify the right registration number
Look for the identifier issued for VAT registration on the supplier’s tax documents, rather than assuming that any number headed “tax ID” is a VAT number. An invoice reference, a company-registration number and another tax identifier can have different purposes. Ask the supplier which authority issued the identifier when the label is unclear.
There is no single worldwide VAT-number format. Check the responsible jurisdiction’s format and validation service, then compare the registered business details where the service provides them. A plausible sequence of letters or digits is not evidence that the supplier is currently VAT-registered. Do not copy an example number into a real invoice.
Frequently asked questions
Is a VAT number the same as an invoice number?
No. A VAT number identifies a tax registration. An invoice number identifies a billing document; a business can issue many invoices under one VAT registration.
Does every VAT registration number use the same format?
No. Format and validation depend on the jurisdiction. Use the responsible tax authority’s guidance and verification service rather than applying a format example from another country.
Where should I find a supplier’s VAT number?
Check the supplier’s tax invoice or registration documentation and confirm which authority issued the identifier. Where an official verification service is available, use it to check the registration details.