Steuer-ID and Steuernummer are constantly confused — and with good reason: both translate as “tax number”, both come from the tax office, and both consist of digits. The difference is simple and important.
The Steuer-ID is a person’s identification number. It stays with you for life and never changes: neither when moving house, nor upon changing your surname, nor in the event of divorce.
Steuernummer is a tax file number. It belongs not to you, but to your file at a specific tax office, and it changes when the office changes.
Below is what each of them means, where to find it, what to do when moving, and what other two numbers appear if you are self-employed.
What is in this article
- Steuer-ID: a lifelong personal number
- Steuernummer: your file number at the tax office
- What each number looks like
- What happens when you move house
- All four numbers in one table
- Three real-life examples
- How to find out or recover your number
- Why your insurer and your Krankenkasse (statutory health insurer) need the Steuer-ID
- Business numbers: USt-IdNr and W-IdNr
- Frequently asked questions
Steuer-ID: a lifelong personal number
The full name is steuerliche Identifikationsnummer. These are eleven digits assigned by the Bundeszentralamt für Steuern, the federal tax office. In documents, they are printed in four groups.
The number is allocated automatically: to a child — shortly after birth, to someone who has moved to Germany — after the first registration of residence. There is no need to submit an application; the letter arrives at the registered address within a few weeks.
Main property: it never changes. Neither when moving within Germany, nor upon a change of surname, nor upon marriage or divorce. Even when leaving the country, the number is retained—if you return after ten years, it will be the same. The data itself is stored for up to twenty years after the end of the year in which a person died.
Where it is needed: for the employer to calculate payroll tax, for the bank when opening an account, for the Krankenkasse, for the Familienkasse (family benefits office) for Kindergeld (child benefit), and for the tax office when submitting a tax return. Without it, the employer is obliged to calculate tax using the most unfavourable tax class VI.
Please note: there is no personal information whatsoever in the number—neither year of birth, nor gender, nor city. It is simply an identifier.
Steuernummer: your file number at the tax office
The Steuernummer is not issued by a federal authority, but by a specific Finanzamt (tax office) — the one responsible for your place of residence. It is an administrative reference for your file: the tax office uses it to locate your records.
The format depends on the federal state: usually ten to eleven digits, written in three groups separated by slashes. In electronic submission via ELSTER, a single federal format of thirteen digits is used — it is the same number, just written differently.
When it appears: upon first filing a tax return, when registering a business, and also if the tax office opens a file for you on its own initiative. Many employees who have never filed a return simply do not need a Steuernummer — and do not have one.
When it changes: when moving to the district of another Finanzamt, when switching to joint taxation with a spouse, when starting a business — a separate number is issued for entrepreneurial activities, in addition to the personal one.
What each number looks like
This is the most common question: a letter from the tax office is full of digits and it is not obvious which line is which number. They can be told apart by length and by separators.
- Steuer-ID — 11 digits, no letters and no slashes. In the letter they are printed in four groups, like 12 345 678 901. On German forms the line is called Identifikationsnummer, IdNr. or Steuerliche Identifikationsnummer.
- Steuernummer — 10 or 11 digits separated by slashes. The form depends on the federal state: 12/345/67890 or 123/456/78901. In ELSTER the same number is converted into a single federal 13-digit form: four digits of the tax office number, then 0, then the district number, the distinguishing number and a check digit.
- USt-IdNr — the letters DE and nine digits: DE123456789.
- W-IdNr — the same form plus a five-digit ending after a hyphen: DE123456789-00001. The ending distinguishes different business activities of the same person.
A practical rule: if the line contains slashes, it is the Steuernummer, the number of your file, and it changes when the tax office changes. If it is 11 digits with no slashes, it is the Steuer-ID, and you have one for life.
What happens when you move house
You’ve moved to another town or area, and your file is transferred to the new tax office. They open it under a new number, and the old one is closed. You don’t need to do anything specially: the tax office learns about the move from your registration at your place of residence.
What is important in practice:
- Submit last year’s tax return to the new tax office — the one where you are registered at the time of submission, rather than where you lived in the tax year.
- The new number will arrive by post or will appear in the response to the first submitted tax return. There is no need to request it separately.
- The Steuer-ID remains unchanged in the process — there is no need to tell the employer or the bank.
- Old documents remain valid. The former Steuernummer on tax certificates from previous years stays as it is, and there is no need to have them amended.
All four numbers in one table
Three real-life examples
First example. You have arrived in Germany and started work. After you register your address, the letter with your Steuer-ID arrives automatically. You give this to your employer, and they calculate the tax according to your tax class. At this point, you most likely do not have a Steuernummer, and you don’t need one: the employer is responsible for payroll tax. The number will be generated when you submit your tax return for the first time.
Second example. You have moved from Munich to Hamburg. The Steuer-ID has remained the same — there is no need to tell your employer anything. Your file was transferred to the Hamburg tax office, which has assigned a new Steuernummer. You will submit your tax return for last year in Hamburg. Nothing needs to be requested; it all happens automatically upon re-registration.
Third example. You have registered a Gewerbe (trade business) or started working as a freelancer. Here, the number of reference numbers increases. Your personal Steuer-ID remains. To this is added a separate Steuernummer for your business activity—this is assigned after submitting the questionnaire Fragebogen zur steuerlichen Erfassung. If you work with businesses from other EU countries, you will also need an Umsatzsteuer-IdNr. And since November 2024, those engaged in business activities have been gradually and automatically assigned a Wirtschafts-IdNr. More details— in our guide to registering as self-employed.
The tax authorities will issue the numbers, but choosing your health insurance when you go self-employed is up to you. In a statutory Krankenkasse a self-employed person pays the whole contribution alone, and at the reduced rate there is no Krankengeld (statutory sick pay) either. In return you get a choice that an employee on an ordinary salary doesn’t have: GKV (statutory health insurance) or PKV (private health insurance), whatever your income.
My advice: if in doubt, stay in GKV — after 55 there is almost no way back from private cover. The figures for both systems are in our guide to health insurance for the self-employed. Book a consultation before you apply to a private insurer: the next insurer’s form will ask about any earlier refusal.
How to find out or recover your number
The easiest way to find your Steuer-ID is in your documents:
- Lohnsteuerbescheinigung — annual certificate from the employer, the number is at the top.
- Einkommensteuerbescheid - tax office decision on the tax return.
- Letter from the Bundeszentralamt für Steuern, which comes after the birth of a child or after the first registration of address in Germany.
- Kindergeld certificate or Krankenkasse documents.
If you couldn’t find it anywhere, the number can be requested again on the Bundeszentralamt für Steuern website via the contact form. The reply is sent only by letter to the registered address — for data protection reasons, the number is not given out over the phone, by email, or in reply to an email. Allow a few weeks for this.
Steuernummer — look for it in the assessment notice for your tax return or in any letter from your tax office. If there is none at all, your file has not been opened yet — that happens after your first tax return. You can check with your local tax office by providing your Steuer-ID.
Why your insurer and your Krankenkasse (statutory health insurer) need the Steuer-ID
It is not only the employer who asks for the Steuer-ID. Ever since contributions to health and pension cover have been counted in the tax return as Sonderausgaben (special expenses), insurers and Krankenkassen report those amounts to the tax office themselves — and they do it using your number.
- Health and Pflege (long-term care) insurance. Under § 10 Abs. 2b EStG the insurance company, or the carrier of the statutory insurance, acts as the mitteilungspflichtige Stelle (reporting body) and reports the amount of contributions paid and refunded during the year.
- Pension contracts of the basic type. Under § 10 Abs. 2a EStG the provider reports the contributions paid together with the certification number of the contract.
- Your number is the key to the transfer. Under § 93c Abs. 1 Nr. 2 Buchst. c AO the data set must contain the surname, first name, date of birth, address and “dessen Identifikationsnummer nach § 139b” — that is, the Steuer-ID.
The practical conclusion is simple: when an insurer asks for your Steuer-ID while setting up a contract, that is not a spare box on the form. Without it the contributions are not matched to your file at the tax office, and the deduction has to be evidenced with paper certificates instead of appearing in the return by itself.
What exactly is deductible, and up to which limits — that is covered on the page about tax classes. The contributions themselves run through contracts: statutory health insurance, private health insurance and pension contracts.
Business numbers: USt-IdNr and W-IdNr
If you work for yourself, two more are added to personal numbers. A private individual does not need them.
Umsatzsteuer-Identifikationsnummer (VAT identification number) — number for transactions with businesses from other EU countries. It starts with DE and contains nine digits. It is issued free of charge, upon application to the Bundeszentralamt für Steuern or directly on the form when registering a business. It is needed to issue and receive invoices without VAT within the European Union and so that the counterparty can check you in the European database.
Wirtschafts-Identifikationsnummer (business identification number) — a new single number for anyone engaged in economic activity. It looks like an Umsatzsteuer-IdNr. with a five-digit ending separated by a hyphen: the ending distinguishes between multiple activities of the same person.
- From November 2024 it started being assigned to those who are already registered for VAT or use the small business regulation under Section 19 of the German VAT Act (UStG).
- From the fourth quarter of 2026 the number is issued to those who pay Körperschaftsteuer (corporation tax), for example a GmbH, or who have to file a Feststellungserklärung (declaration for the separate determination of income). Everyone else engaged in an economic activity will receive it from the fourth quarter of 2027.
- You do not need to submit an application — assignment happens automatically.
- It does not replace the Umsatzsteuer-IdNr. yet and operates in parallel.
Frequently asked questions
What is the difference between the Steuer-ID and the Steuernummer, in one sentence?
The Steuer-ID is a personal number: you have only one, and it is for life. The Steuernummer is a file number at a specific tax office; it changes whenever your tax office changes.
I don’t have a Steuernummer — is that alright?
Yes. An employee who has never filed a tax return might not have one at all. The number will appear upon filing the first tax return or registering an activity.
Does the tax identification number (Steuer-ID) change when changing one’s surname or upon divorce?
No. It does not change under any circumstances.
I’ve lost the letter with the number. Can I find it out over the phone?
No. The Bundeszentralamt für Steuern only sends the number by post to the registered address — those are the data protection requirements. The quickest way to check is on your employer’s certificate or in your tax assessment notice.
Does a child have their own Steuer-ID?
Yes, it is allocated shortly after birth. The number is needed, among other things, for applying for Kindergeld.
What happens if you don’t give your employer your Steuer-ID?
The employer is obliged to apply tax class VI, which is the least favourable. The overpayment can be claimed back later via a tax return, but it is easier to provide the number straight away.
Do I need a VAT identification number (USt-IdNr.) if I am a freelancer with only German clients?
No. It is needed for transactions with businesses from other EU countries. For work within Germany, a Steuernummer is sufficient.
About the author. Valery Melech, Finber. Versicherungsmakler (insurance broker) licensed under Section 34d (1) of the German Trade Regulation Code (GewO) and Immobiliardarlehensvermittler (real estate finance broker) under Section 34i GewO, registered with the IHK Rhein-Neckar (Chamber of Industry and Commerce). Over 20 years of experience, around 6’000 clients, and upwards of 400 partners.
Sources. Federal Central Tax Office — Tax Identification Number: eleven digits, no personal data within the number, retention for up to twenty years after death, notification of the number by letter only. Federal Central Tax Office — Economic Identification Number: format, timeline for assignment, lack of necessity for an application. Legal basis — Sections 139b and 139c of the Fiscal Code (AO).
Status. The data was verified in August 2026. The section on the Wirtschafts-IdNr. will be updated after the next allocation stages (the fourth quarter of 2026 and of 2027).
This material is for informational purposes only and does not constitute individual advice.
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What type of document do I need from my employer for income tax relief, or I don’t know, what money can we claim a tax refund on?
I would like to come to you with this document and, if possible, explain to me what this document is called in German so that I can ask my employer to give it to me, and how much do I pay for your services?
Thank you very much
Hello.
To submit your tax return, you will likely need a document from your employer that shows your income for the year. This document is often called an income statement or income form. In Germany, such a document is called a Lohnsteuerbescheinigung.
You will need a tax adviser for the preparation of your tax return, I cannot help you with that.
As for the cost of services for preparing and submitting your tax return, it may vary depending on the complexity of your financial situation and the tax adviser you choose. Some advisers charge an hourly rate, while others offer fixed fees for their services.
I’ve lost my tax number