Your German tax ID (Steuerliche Identifikationsnummer, IdNr; the BZSt calls it IdNo in English) has 11 digits and comes from the Federal Central Tax Office (Bundeszentralamt für Steuern, BZSt). You don't apply for it: once you have registered your address at the Bürgeramt (Anmeldung), the BZSt sends it by post. Your employer needs it for your wage tax; without it, tax class VI applies. No letter after three months? Request it again. It's not your social security number, and it's not the Steuernummer (the number your local tax office uses).
Federal Central Tax Office (identification number, questions and answers, online portal “Obtain tax identification number”), Federal Ministry of Finance (tax changes 2026); law: § 139b AO, §§ 39c, 40a, 32a EStG. All checked on 21 September 2026. Links at the bottom.
Eleven digits, and they say nothing about you: no date of birth, no town, no tax office. The BZSt calls it a “non-speaking number”. It is valid for life. Moving, marrying, a new name: the number stays. The law allows exactly one per person (§ 139b AO).
Don't mix it up with two others. The Steuernummer is a different number, issued by your local tax office (Finanzamt), not by the BZSt. If a form says “Steuer-ID”, “IdNr” or “Identifikationsnummer”, it means the 11-digit one. And the Sozialversicherungsnummer has twelve digits and comes from the pension insurance: how you get that one.
Not on your health insurance card, not on your passport or residence permit.
You don't get a new number, you already have one. The BZSt tells you the same number again: through the BZSt online portal (service “Obtain tax identification number”, in German “Erneute Mitteilung der steuerlichen Identifikationsnummer”), or by letter to the BZSt. The answer comes by post only, never by e-mail or phone, for data protection reasons. To an address other than your registered one it is sent only with a written authorisation and a copy of your ID.
New in Germany, registered your address three months ago and still no letter? Then you can request the number through the same form. And if a tax return is due before the letter arrives: you can file without the number, your tax office can look it up.
For your wage tax. With your tax ID and your date of birth the employer retrieves your electronic wage tax data (ELStAM) from the BZSt, including your tax class. That decides what is deducted from your pay.
If the number is missing because you didn't provide it, the employer has to use tax class VI (§ 39c EStG), the least favourable one. If it's not your fault, for example because the letter is still on its way, your employer may deduct wage tax on the tax class they expect to apply, for up to three calendar months. Once the number arrives, the difference is settled in the next payslip. If it never arrives, tax class VI applies retroactively.
Short-term jobs can be taxed a different way: the employer may pay a flat wage tax of 25 percent (§ 40a EStG) if the job is occasional, not regularly recurring, lasts no more than 18 consecutive working days, the pay averages no more than 150 euros a day and the hourly wage is not above 19 euros. Then your tax class isn't used for that job. Whether your employer does that is their call; ask, or look at your contract. At echt Personal it runs through your tax class.
The money question: in 2026, income tax starts only above a taxable income of 12,348 euros a year, the basic allowance (§ 32a EStG). If you stay below that and wage tax was still deducted, you can get it back with a tax return. Whether you have to file one at all is a question for a separate page, which we'll publish once it has been checked.
You work a few weeks in Germany but live abroad and don't register an address here? Then the letter doesn't come by itself, because no registration office sends your data to the BZSt. In that case the tax office responsible for your employer (Betriebsstättenfinanzamt) can have the number issued. It has to be applied for, usually by your employer. The BZSt explicitly names short-term employed students as an example. The form is called Vordruck 010250 “Antrag auf Vergabe einer steuerlichen Identifikationsnummer für nicht meldepflichtige Personen”, available on the form server of the federal tax administration, formulare-bfinv.de (search for 010250).
No. It comes automatically by post after your first registration of an address in Germany (Anmeldung), as soon as the registration office has passed your data to the Federal Central Tax Office.
The BZSt itself works with a three-month mark: if three months have passed since your Anmeldung and there is no letter, you can request the number from the BZSt. The answer comes by post only.
If it is not your fault, your employer may calculate the wage tax on estimated data for up to three months. Once the number is there, the difference is settled in the next payslip. If you simply did not provide it, tax class VI applies.
No. Tax ID: 11 digits, Federal Central Tax Office, wage tax. Social security number: 12 characters (11 digits and a letter), pension insurance, social insurance. The staff questionnaire asks for both.
No. It is valid for life. Even if you leave Germany and come back years later, it is the same number. Every person gets exactly one.
Yes. Then the tax office responsible for your employer (Betriebsstättenfinanzamt) can have one issued. It has to be applied for, usually by your employer, with form 010250 for persons who are not required to register. The BZSt names short-term employed students as an example.
Susanne Schmidt-Dizdarevic. Authorised officer (Prokuristin) of echt Personal GmbH, responsible for HR. Trained hotel specialist, in staffing since 2009. Signs short-term employment contracts with students and school pupils every week.
Paid too much wage tax, for example in tax class VI? How to get it back with a tax return.
The other number in the staff questionnaire: your German social security number. Minijob or short-term job, which one fits you: explained here (in German).
At echt Personal the tax ID is on every staff questionnaire, right next to the social security number. We tax short-term jobs through your tax class, not with the flat rate, so we need the number before your first payslip. Without it, tax class VI applies. Looking for a side job right now: jobs in your city.