How you get a tax number
You do not apply for the tax number for your self-employment with a separate application. You receive it once you send the tax office the tax registration questionnaire (Fragebogen zur steuerlichen Erfassung). With it, the tax office registers you as a business, assigns a tax number (Steuernummer) and sends it to you by post. The questionnaire is the registration, the number is the reply.
This applies to freelancers and traders alike. Even if you start on the side or work under the small business rule without charging VAT, you need it. So plan the questionnaire into your first weeks, ideally before your first job is done. With luck, the number is already there when you write your first invoice.
The deadline: one month
Anyone who takes up a freelance activity tells the tax office (§ 138 Abs. 1 Satz 3 AO). Anyone who opens a trade notifies the municipality (§ 138 Abs. 1 Satz 1 AO). These notifications are due within one month (§ 138 Abs. 4 AO).
On top of that comes the information about your tax situation, which is the questionnaire itself. It is also due one month after you start, and you file it electronically in the official data format (§ 138 Abs. 1b AO). In practice that means through Mein ELSTER. The tax office allows paper only in cases of hardship.
What counts as the start is when you take up your work, not the day of the first payment.
Trade or liberal profession: who registers where
| You are | Trade office | Tax office |
|---|---|---|
| Freelancer in a liberal profession | no registration | questionnaire in Mein ELSTER |
| Trader | trade registration (§ 14 GewO) | questionnaire in Mein ELSTER |
The trade registration does not replace the questionnaire. The trade office passes your registration on to the tax office among others, but you still provide the tax details yourself. Whether your work counts as a liberal profession or a trade is explained in the guide freelancer or trade.
What the questionnaire asks
The questionnaire looks long, but most questions are quick to answer. These are the ones that matter:
- Your work: Describe concretely what you do, for example “development of web applications for businesses” instead of “IT”. The tax office uses this to classify you as a freelancer or a trade.
- Turnover and profit: You estimate them for the year you start and the following year. From the profit, the tax office sets your income tax prepayments. A realistic estimate protects you from high prepayments and from a large back payment.
- Small business rule: You decide whether to use it. In the year you start, that works as long as your turnover does not exceed €25,000 (§ 19 UStG). More in the guide on the small business rule.
- Accrual or cash accounting: Without the small business rule, you can apply here to pay VAT only when your customers pay (§ 20 UStG).
- VAT ID: If you work for businesses in other EU countries, apply for it right away. It comes from the Federal Central Tax Office (BZSt) once the tax office has registered you.
- Profit method: Most self-employed people choose the profit statement (EÜR).
Set aside an hour or two of quiet time and have your bank details, your tax ID and a rough plan of your income ready. Usually just the estimates feel uncertain, and you can adjust them later.
The tax office sets your VAT return period from your answers. For businesses started up to the end of 2026, it goes by the VAT you expect for the current year: above €9,000 you file monthly, otherwise usually quarterly (§ 18 Abs. 2 UStG).
Until the tax number arrives
Between questionnaire and number there are often a few weeks. During that time you lack a mandatory detail: every invoice needs your tax number or your VAT ID (§ 14 Abs. 4 Satz 1 Nr. 2 UStG). An invoice without either is incomplete. For a customer who deducts input tax, that is a real problem.
This is how you get through the wait:
- Work as usual and keep a record of what you delivered.
- Write the invoice as a draft and finalize it as soon as the number arrives.
- If time is pressing, talk to your customer. Many would rather wait a few days than record an incomplete invoice.
- If the number does not come, ask the tax office about the status. A short call often shows whether anything is missing.
What else belongs on an invoice is in the guide on invoice requirements.
Tax number, tax ID and business ID
Three numbers are often mixed up:
- The tax identification number (Steuer-ID) is yours as a person and has been for years. It has eleven digits and does not belong on your invoices (§ 139b AO).
- The tax number (Steuernummer) is assigned by your tax office for your tax returns. If you move to another tax office’s district, it can change.
- The business identification number (Wirtschafts-Identifikationsnummer, W-IdNr.) has been assigned automatically, step by step, by the Federal Central Tax Office since November 2024. You do not apply for it. It starts with “DE” and does not replace your tax number on invoices. If you already have a VAT ID, it becomes part of the business ID, extended by a five-digit distinguishing suffix.
This guide explains the rules in general and is not tax advice. How the tax office classifies your answers depends on your case.
Common questions
Do I need the questionnaire for a side business too?
Yes. The duty depends on taking up a self-employed activity, not on its size. A side business next to your job also needs a tax number as soon as you write invoices.
What if I miss the deadline?
File the questionnaire as soon as you can. The deadline is a duty, not a recommendation. Above all, your tax number is delayed, and with it every complete invoice.
How long does it take to get the tax number?
That depends on the tax office. Often it takes a few weeks, longer with follow-up questions. The clearer your description of your work, the less often the tax office asks back.
Can I change my estimate later?
Yes. If you notice that turnover or profit develop quite differently, you can ask the tax office to adjust your prepayments. The final tax only follows from your tax return anyway.