Tax number, tax ID and business identification number

In short: The tax ID has 11 digits and applies for life to every person. The tax number is assigned by the tax office for a particular tax type and business. The business identification number is meant to identify companies uniquely in future.

In more detail: Everyone registered in Germany automatically gets a tax identification number, children included. It appears for example on letters from the Federal Central Tax Office. For the business, the tax office assigns a tax number after the questionnaire and, if necessary, a VAT identification number.

In detail

• Tax ID: never changes, stays for life. Finding it again: letter from the Federal Central Tax Office, wage tax certificate, tax assessment, or ask the Federal Central Tax Office.
• Tax number: appears on notices and must be stated on invoices (alternatively the VAT ID).
• VAT ID: needed for intra-EU transactions and some business partners. Small businesses often have none.
• Business identification number: being introduced step by step and will in the long term replace the tax number for companies.
• Invoice: without tax number or VAT ID the invoice is formally defective (Writing an invoice (mandatory details under § 14 UStG)).

See also: Tax registration and the ELSTER questionnaire, ELSTER: registration and certificate