The questionnaire for tax registration (Fragebogen zur steuerlichen Erfassung) is the form you use to register a self-employed or trade activity with the tax office. Your answers give the tax office the basis on which your tax number, VAT advance returns and prepayments are later built.
Short answer: In the questionnaire you state your address and bank details, estimate your expected turnover and income, and name your legal form. A VAT identification number (USt-IdNr.) is optional. The tax office then assigns your tax number. The legal basis is the notification duty under § 138 AO. Last updated: November 2026.
The most important points
- The questionnaire is the formal registration of your self-employed activity with the tax office.
- Your figures for turnover and income influence how the tax office sets VAT and prepayments.
- According to the IHK, you should return the completed questionnaire within one month.
- You only need a VAT identification number for cross-border trade within the EU, and you apply for it separately.
- The tax office needs your legal form from the start.
Which details does the questionnaire ask for?
The required details are manageable. According to the IHK Fulda leaflet on starting a trade activity (in German), they include general details about you and your business, the expected turnover and income, and your legal form. The page does not show a date. Check the current form with your tax office before you send it.
| Detail | What the tax office uses it for |
|---|---|
| Address and bank details | Assigning tax data and delivering notices |
| Expected turnover and income | Deciding VAT advance returns and prepayments |
| Legal form | Classifying the business as a partnership (e.g. GbR, OHG, KG) or a corporation (e.g. GmbH, AG) |
| VAT identification number (optional) | Application for cross-border supplies and acquisitions within the EU |
How do you estimate your turnover realistically?
Your estimate should be traceable. The tax office uses your figures as the basis for its assessment, and changed circumstances can be reported later. If you earn little in the first year, do not enter a high figure just to avoid prepayments. Figures that are too low tend to stand out later in the process as well.
Assumption: you expect 6,000 euros of income in the first year from a side business and plan business expenses of 1,500 euros. Your expected profit is then 4,500 euros. This is an estimate for the registration, not a tax calculation, because your tax depends on your total income.
Which deadlines apply after you send the form?
According to the IHK leaflet, the completed questionnaire must be returned within one month. After that, the tax office assigns your tax number. A VAT identification number takes up to two months according to the same source. If you apply by fax and the tax office confirms receipt, the page says it can take about three days.
| Step | Timeframe according to the IHK leaflet |
|---|---|
| Return the questionnaire | within one month |
| Tax number | assigned by the tax office after receipt |
| VAT identification number | up to two months |
| Application by fax with confirmation | about three days |
How does the notification duty fit into the law?
The notification duty rests on § 138 AO, which covers notification of gainful activity. For freelance work, § 18 EStG is also relevant, because it describes income from self-employed work. The small-business rule in § 19 UStG is also mentioned in the questionnaire. We explain its current limits in our guide on the small business regulation.
Whether your activity counts as a trade or as a freelance profession depends on what you actually do, not on the name you give it. The classification affects what the questionnaire needs, so settle it before you file.
Frequently asked questions
Do I need to fill in the questionnaire as a student?
Yes, as soon as you take up a self-employed activity. A mini-job as an employee does not require a questionnaire for tax registration. Whether an activity counts as a freelance profession depends on its nature, and we cover that in a separate guide.
Can I submit the questionnaire online?
Ask your tax office which submission route applies to you. Clarify open questions directly with the responsible officer rather than adding them to the form.
What happens if I miss the deadline?
If you miss the one-month deadline, contact the tax office and ask for an extension or a short clarification. This is easier than correcting a file that has already been opened.
Do I have to report changes later?
You should tell the tax office promptly about changes, for example to your legal form, your address or your expected turnover. The tax office will tell you on request which form applies.
Does a tax adviser help with the form?
That is possible if you are unsure which details are correct. For simple side activities, advice from the tax office is often enough. Whether an adviser is worth it in your case depends on the scope of the activity.
Which mistakes happen often?
The same points come up again and again. They usually cost only time, but they can trigger queries that are easy to avoid.
- Turnover is guessed without a calculation and without a look at the actual costs.
- The legal form is chosen according to the name you like, not according to how the business is organised.
- A VAT identification number is applied for although no cross-border business is planned.
- The form is sent without a copy. Keep a copy and the proof of dispatch so you can document the status later.
A short list of figures, details and dates before you start saves corrections later. Note the reasons for your estimate, because they help you answer any follow-up questions from the tax office.
When do you need a VAT identification number?
The VAT identification number (USt-IdNr.) is optional in the questionnaire. You mainly apply for it if you exchange goods or services with businesses in other EU countries. According to the IHK leaflet, this concerns cross-border transactions. The page gives the acquisition threshold for intra-EU purchases as 12,500 euros per calendar year under § 1a para. 3 no. 2 UStG.
If you supply only private customers or businesses in Germany, you usually do not need the number. If you are unsure whether a transaction falls under the rule, clarify it with the tax office before registering, because the number affects invoices and reports.
What applies to a side job next to your studies?
Many students ask whether a side job triggers the questionnaire. The type of work decides. If you work as an employee, for example in a mini-job or as a student employee, you do not register yourself with the tax office, because the employer handles the payroll. It is different when you provide services on your own account, such as texts, translations or consulting for several clients.
For these activities, the details in the questionnaire matter, because the tax office has to assign them to a tax type. If you hold a mini-job and also work independently on the side, keep the two strictly apart. Our guide on bogus self-employment explains where the line between employment and an assignment runs.
How to proceed now
- Note your address, bank details and the legal form you want.
- Estimate your turnover realistically and set the expected costs against it.
- Decide whether you need a VAT identification number.
- Send the questionnaire within the one-month deadline and note the date.
Related guides
- Founding a business alongside your studies
- Small business regulation 2025: new limit of 25,000 euros
- Bogus self-employment: how to spot it in assignments
- Income-surplus accounting for side jobs (in German)
- Freelancing as a Student: How to Land Your First Orders
Sources: IHK Fulda leaflet on starting a trade activity, no date given (in German), § 138 AO, wording on steuertipps.de (in German).
Last updated: November 2026. This guide is general information, not individual advice.
