§ 139b AO · Federal Central Tax Office
The tax identification number is automatically assigned by the Federal Central Tax Office – as soon as you are registered. It arrives by post and takes up to four weeks you need them from the first day of work. Register first. The tax ID comes automatically.
Automatically after registration: Registering your apartment at the Citizens' Registration Office → Federal Central Tax Office issues tax ID → Letter arrives at the registered address within 2-4 weeks
Once and for life: The ID number remains the same – if you change jobs, move, get married or change your name. It applies for your entire life in Germany.
Common Error: Start work without a tax ID → Employer taxes according to tax class VI (highest rate) → significantly lower net salary until subsequent submission
Confusion: Tax ID (IdNr) ≠ tax number. The tax number is assigned by the tax office and changes when you move. Employer needs the tax ID, not the tax number.
Basics
The tax identification number (IdNr) is a permanent, eleven-digit number that... The Federal Central Tax Office (BZSt) allocates it once to every person registered in Germany. It is not the same as the tax number, which the local tax office issues for the income tax return.
The ID number consists of 11 digits and never starts with a zero. It is awarded once and does not change - not even if you move within Germany, get married or divorced.
You need it wherever you appear for tax purposes: at your employer, at the tax office, for child benefit, for building savings and for certain banking products.
| feature | Tax ID (IdNo) | Tax number |
|---|---|---|
| Awarded by | Federal Central Tax Office (BZSt) | Local tax office |
| Validity | Lifelong, unchanging | Changes when moving (different tax office) |
| positions | 11 digits | 10-13 digits (depending on the federal state) |
| Why? | Employer, child benefit, capital gains | Income tax return (ELSTER) |
| Automatically? | Yes – after registering your apartment by post | No – only after the first tax return or upon request |
Uses
Tax ID is not an optional data point. You are in several areas of life legally requiredto declare them – or there will be financial disadvantages.
Work, account, child benefit & more
The employer is legally obliged to transmit the employee's tax ID to the tax office. If it is not available, it must automatically Tax class VI apply – the most unfavorable rate, which can mean up to 45% income tax.
After submitting the tax ID, any excess tax paid will be refunded in the annual tax return - but the net salary will be lower until then.
The tax ID is required for the exemption order for capital gains (interest, dividends). Without them, the bank holds on Withholding tax (25% + solidarity surcharge) automatically.
Step by step
The tax ID will be only for registered people awarded. If you don't register your apartment, you won't get a letter from the Federal Central Office. Registration within 14 days of moving in - appointment at the residents' registration office/citizens' office of the responsible city.
First look for an apartment, then move in, then register. Without a fixed address, there is no registration form – without a registration form, there is no tax ID.After registration, the residents' registration office automatically transmits the data to the Federal Central Tax Office (BZSt) in Bonn. The BZSt issues the tax ID and sends it by simple letter to the registered address. Duration: 2-4 weeks. No application, no fee, no need to go to the authorities.
If you have not received a letter after 4 weeks, you can request the tax ID from the BZSt again - exclusively by post or via the online form on the BZSt website. Information by telephone is not possible for data protection reasons. The tax ID will then be delivered again to the reported address.
The letter will be sent to the registered address - not to a desired address. First check whether the registration was registered correctly.Do you have to start work before receiving your tax ID? Inform your employer in writingthat the tax ID has been applied for and is in the mail. Many employers accept this for a few weeks. After receipt: Submit your tax ID immediately. Excessive payroll tax (Class VI) will be refunded via the annual tax return.
The ID number is on a simple letter without an envelope window - it often looks inconspicuous. Write down the number immediately and store in a safe place. If lost: Apply for new delivery using the BZSt form. The number itself never changes.
Timeline after entry
From entry to the first tax return – the most important points in time.
Apartment registration – basis for everything
Without registration, no tax ID, no bank account (in many cases), no ABH documents. Priority 1 after entry. Book an appointment at the Citizens' Office.
Letter with tax ID comes in the mail
The Federal Central Office sends the ID number automatically. No application necessary. Letter to the registered address - not somewhere else.
Empty the mailbox every day – the letter looks inconspicuous.Submit tax ID to employer
The employer enters the ID number in the electronic wage tax deduction features (ELStAM). Without her: Tax class VI – highest deduction. Send it in as soon as the letter arrives.
Submit an exemption request to the bank
Capital gains up to €1,000 (individual) / €2,000 (couples) remain tax-free – if an exemption order with a tax ID is stored. Otherwise withholding tax of 25%.
Application for child benefit at the family fund
Who is entitled to child benefit: ID numbers of both parents and all children is mandatory information on the form. The application will not be processed without complete information.
Income tax return via ELSTER
The tax ID is the identification feature at the tax office. Mandatory field in ELSTER and on the paper form. Often worthwhile for employees – advertising costs, flat rates, reimbursements possible.
Special cases
The tax ID is the same for life. If the letter hasn't arrived or the number has been lost, there is a clear path to recovery – exclusively via the Federal Central Tax Office.
Apply for new delivery – free of charge
There is one on the website of the Federal Central Tax Office (bzst.de). Online redelivery form. You provide your name, date of birth and current address. The tax ID is then sent by simple letter to the registered address.
Letter to the Federal Central Tax Office, 53221 Bonn. Contents: Full name, date of birth, current registration address, request for the tax identification number to be sent again.
Tax brackets
The tax ID is the link between you and the ELStAM system – the electronic process through which the employer retrieves your income tax class. The tax class determines how much income tax is deducted each month.
Tax classes I to VI – what applies and when
| class | For whom | Deduction |
|---|---|---|
| Class I | Single, divorced, widowed (after the 1st year) – standard for most immigrants | Means |
| Class II | Single parents with children in the household (relief amount) | Slightly lower than I |
| Class III | Married – higher-earning partner (combined with Class V) | Low |
| Class IV | Married people – both partners have similar income | Same as class I |
| Class V | Married – low-earning partner (combined with Class III) | High |
| Class VI | Second or further job – or: the employer does not have a tax ID | Highest deduction |
For most immigrants, this is automatic for their first job in Germany Tax class I. It is deposited via the ELStAM system as soon as the employer has the tax ID.
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As of: May 2026. Lalmano checks content editorially and is based on official information, including from Foreign Office, BAMF and Make it in Germany. The content does not replace individual legal advice.