The VAT-ID (= value added tax identification) is a number used as as an identifier for value added tax purposes.
The number identifies a taxable person/business or non-taxable legal entity that is registered for VAT. Therefore it fulfills following functions:
- identification of the tax status of the customer
- helping to identify the place of taxation
- being mentioned on invoices (except simplified invoices in certain EU countries)
Every EU country issues its own national VAT number. This means that business supplying goods or services in several EU countries might be liable to get a VAT number in each of these countries.
The full identifier starts with the 2 letter ISO 3166-1 alpha-2 county code and then has between 2 and 13 characters (mainly numeric digits, but in some countries also with letters)