As soon as you arrive in Germany, the HR department asks for two numbers: the Steuer-ID (tax ID) and the social insurance number (Sozialversicherungsnummer). Both are easy to get, but if you do not know the rules you can easily lose money in your first month. Here is everything important at a glance.
As of October 2026. General information, not legal or tax advice.
In short: the Steuer-ID (11 digits) arrives automatically by post from the Federal Central Tax Office after you register your address – usually within a few weeks. The social insurance number is assigned when your employer registers you with a health insurance fund; the confirmation also arrives by post. If the Steuer-ID is missing, your employer often uses tax class VI for a while. Both numbers are valid for life – keep the letters safe.
The two numbers at a glance
| Steuer-ID | Social insurance number | |
|---|---|---|
| Official name | Steuerliche Identifikationsnummer (IdNr) | Versicherungsnummer of the pension insurance |
| Format | 11 digits | 12 characters (digits and one letter) |
| Issued by | Federal Central Tax Office (BZSt) | German Pension Insurance (Deutsche Rentenversicherung) |
| When | After registration at the Bürgeramt | When you are first registered for social insurance |
| Used for | Income tax, tax return, bank, child benefit | Pension, health insurance, unemployment insurance |
| Validity | For life | For life |
Steuer-ID: how to get it
- Registration at the Bürgeramt: within two weeks of moving in you must register your address. How it works is explained in Moving and registration.
- The letter comes automatically: the registration office passes your data to the BZSt, which sends your Steuer-ID by post – in practice usually after two to four weeks.
- Your name on the letterbox: make sure your name is on the letterbox. Otherwise the letter is returned.
Letter lost or never arrived? You can request your Steuer-ID again from the BZSt – via the online form on bzst.de or in writing. For data protection reasons the number is sent only by post to your registered address and is not given out by phone. If you have worked in Germany before, your Steuer-ID is also on old wage tax certificates (Lohnsteuerbescheinigung) or tax assessments.
The Steuer-ID never changes – not after a move, a marriage or years abroad.
Social insurance number: how to get it
You usually do not have to apply for the social insurance number (also called SV-Nummer or Rentenversicherungsnummer) yourself:
- Before you start work, you choose a statutory health insurance fund and tell your employer which one. More in our article on health insurance.
- Your employer registers you with the fund. If you do not have a number yet, the fund requests one from the Deutsche Rentenversicherung.
- The pension insurance sends you a Versicherungsnummernachweis by post. Since 2023 this is the official name of the former social insurance card (Sozialversicherungsausweis).
If you need the number faster, you can also contact your health insurance fund or an advice centre of the Deutsche Rentenversicherung yourself. If you lose the confirmation, the pension insurance will issue a new one.
What your employer needs on day one
If possible, bring the following when you start:
- Passport or ID card – non-EU citizens also need their residence permit with permission to work (for Ukrainians, for example, the residence permit under § 24 or a Fiktionsbescheinigung).
- Steuer-ID and date of birth – your employer uses them to retrieve your tax data.
- Social insurance number, if you already have one.
- Name of your health insurance fund or its membership certificate.
- IBAN for your pay – see Opening a bank account.
- Registration certificate (Meldebescheinigung), if requested.
If something is missing, you can still start. Hand in the numbers as soon as the letters arrive – the sooner, the fewer problems with payroll.
ELStAM: how your employer learns your tax class
ELStAM stands for “electronic wage tax deduction characteristics” – a database of the tax authorities. Using your Steuer-ID and date of birth, your employer retrieves:
- your tax class (Steuerklasse),
- child allowances,
- your religious affiliation for church tax (from what you stated at registration),
- any tax allowances.
You do not need to submit anything yourself. If something changes (marriage, a child, leaving the church), this goes through the registration office or the tax office (Finanzamt).
What happens if the Steuer-ID is missing?
Without a Steuer-ID your employer cannot retrieve ELStAM. Then:
- As a rule, tax class VI is applied. This is the least favourable class – noticeably more tax is withheld.
- Exception (§ 39c Income Tax Act): if it is not your fault that the ID is still missing – for example because you have only just moved – your employer may use your expected tax class (e.g. I) for up to three months. If the ID is still missing after that, class VI must be applied retroactively.
- The money is not lost. Once the Steuer-ID arrives, your employer corrects the following payslips. Any overpaid tax can be reclaimed at the latest with your tax return.
How income tax and social contributions affect your take-home pay is explained in Gross and net.
Tax classes in brief
| Class | For whom? |
|---|---|
| I | Single, divorced, and also married people whose partner does not live in Germany (standard case) |
| II | Single parents entitled to the relief amount |
| III | Married people whose partner is in class V or does not work |
| IV | Married people with similar incomes |
| V | Married people whose partner is in class III |
| VI | Second job or side job – or temporarily without a Steuer-ID |
Tip for married EU citizens: if your spouse still lives in Romania, Bulgaria, Poland or another EU/EEA country, you will usually start in class I. Under certain conditions EU citizens can apply to the tax office to be taxed as a married couple. Whether this pays off depends on both partners’ incomes – if in doubt, ask the Finanzamt or a wage tax assistance association (Lohnsteuerhilfeverein).
Keep the letters safe
You will need the letters with your Steuer-ID and social insurance number again and again: with your next employer, at the bank, for child benefit, for your tax return and later for your pension – even if you have long since returned home.
- Keep the originals at home in a folder.
- Take a photo or scan and store it safely.
- Give the numbers only to employers, authorities, your health insurance fund and your bank – never to strangers in chats or on social media. More warning signs: How to spot fake job offers.
Checklist
- Move in and register your address within two weeks.
- Put your name on the letterbox.
- Choose a health insurance fund and tell your employer.
- Wait for the Steuer-ID letter (usually two to four weeks) and pass the number to your employer immediately.
- Wait for the social insurance number confirmation and pass the number on.
- Check your first payslip: is the tax class correct?
- Keep both letters safe.
For a complete overview of your first weeks, see our first steps in Germany checklist.
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