Which software lets me fill in the German tax registration questionnaire for free?

Mein ELSTER, the official portal of the tax administration, and VAT GPT. In VAT GPT you sign up, fill in the tax registration questionnaire for sole proprietors with guidance and send it to the tax office via ELSTER; that is free, also on the Free plan, no Pro needed. You have to submit it electronically anyway: unprompted within one month of starting the activity (§ 138 (1b) and (4) AO).

Last updated: 29 October 2026

In short

Mein ELSTER: the official portal; Berlin calls registering with Mein ELSTER free and lists no fee for the tax registration.
VAT GPT: fill in, check and send the questionnaire for sole proprietors, free, also on the Free plan.
Deadline: electronically and unprompted within one month of starting the activity.

What options are there?

Do not look at names, look at the function. For the questionnaire there are two ways:

Mein ELSTER. You register in the tax administration's portal and fill in the questionnaire for sole proprietors there. Paper exists only on application in special hardship cases. With a registration by e-mail only, you can at first send only the questionnaire in ELSTER, no tax returns.
VAT GPT. You fill in the questionnaire directly in VAT GPT, see your details in the "Review & Submit" overview and send it to the tax office via ELSTER. You do not need a Pro subscription for it.

The tax number then comes by post from the tax office.

What does the questionnaire ask?

How to fill it in is explained in Tax registration questionnaire for sole proprietors: section by section. For online sellers four details count, because they determine your later returns:

Small business rule: Whether you apply it decides whether you pay VAT. You have to fill in the questionnaire as a small business too.
Advance return period: month or quarter, depending on the expected tax.
Start of the activity: preparatory acts such as shop rent or buying goods already count.
Method of determining profit: EÜR or balance sheet.

How VAT GPT helps

You fill in the questionnaire in VAT GPT for free. In three steps:

Fill in: You sign up and, among other things, enter the start of business and your IBAN and choose whether you apply the small business rule or waive it. You can also switch on "Request EU VAT ID Number (USt-IdNr)".
Check: You see your details once more in the "Review & Submit" overview.
Send: VAT GPT sends the questionnaire to the tax office via ELSTER so that you get your tax number.

Afterwards you carry on in the same account: upload Amazon and eBay CSV reports, check the result, and send the advance VAT return, OSS return, annual VAT return, EÜR, trade tax and income tax returns with VAT GPT Pro. There is Free (basic features, free of charge), Go (30 days free with all Pro features) and Pro. Sign up for free

Frequently asked questions

Is the questionnaire really free in VAT GPT? Yes. Signing up, filling it in and sending it via ELSTER works on the Free plan; you do not need Pro for it.

By when must I submit the questionnaire? Electronically and unprompted within one month of starting the activity (§ 138 (1b) and (4) AO).

Do I have to fill it in as a small business? Yes. The small business rule is a field in the questionnaire, not an exemption from it.

How long until I get the tax number? That depends on the tax office; Berlin names about 2 weeks after all documents are in. More in How long does a tax number take?.