Money & taxes
Steuer-ID
The Steuer-ID (tax identification number) is an 11-digit number every person in Germany receives once and keeps for life. It arrives by post two to three weeks after your first Anmeldung, and your employer needs it to run payroll correctly.
The steuerliche Identifikationsnummer is Germany's lifetime personal tax number, introduced to identify taxpayers uniquely across authorities. It is assigned automatically after your first address registration (Anmeldung) and sent by letter from the Federal Central Tax Office (Bundeszentralamt für Steuern) to your registered address, usually within two to three weeks.
The Steuer-ID is distinct from the Steuernummer, which the local Finanzamt assigns for tax returns and freelancing and which can change when you move. The 11-digit ID never changes, no matter how often you relocate or switch jobs.
What it means for working students
Employers ask for the Steuer-ID on day one. Without it they must tax you at the unfavorable class VI rate until you deliver the number, which temporarily shreds your net pay (the excess comes back via payroll correction or tax return, but why wait). If the letter has not arrived or got lost, you can re-request the ID at the Bundeszentralamt für Steuern online; pick it up in person at the Finanzamt only in urgent cases.