Tax number vs tax ID in Germany: which number goes where?

Not sure which number goes where? The tax number (Steuernummer) comes from your tax office for a case it processes; you find it top left on a notice. The tax ID (Steuer-ID) is an 11-digit number the Federal Central Tax Office (BZSt) assigns to you permanently. ELSTER states explicitly that the two are independent and should not be confused.

Last updated: 27 October 2026

In short

VAT ID (USt-IdNr.): from the BZSt on application, which states the tax number under which you are registered for VAT.
Business ID (W-IdNr.): assigned by the BZSt to economically active persons in stages since November 2024, without application.
Invoice: in principle your tax number or VAT ID, not the tax ID (§ 14 (4) no. 2 UStG).

What is the difference between tax number and tax ID?

	Tax number	Tax ID (IdNr.)
Issued by	the competent tax office	the Federal Central Tax Office
Applies to	the case; several may exist for different taxes	the person, permanently
Format	length varies by federal state	eleven digits
Changes	for example after a move	not through a move, name change or change of marital status
Where to find it	on a notice, top left behind the word "Steuernummer"	income tax notice or wage tax statement

That is the core: the tax number belongs to a case at the tax office, the tax ID to the person.

Where do I find which number?

Tax number: on a notice from your tax office, top left behind the word "Steuernummer". The layout can differ slightly by federal state or tax type. If you do not have one yet, the route is in Tax number in Germany: applying with the tax registration questionnaire online, the waiting time in How long does it take to get a tax number in Germany, and what do you do meanwhile?.

Tax ID: usually on your income tax notice or your wage tax statement. If you cannot find it there, you can request it again through the BZSt's form or by letter. For data protection reasons it is only sent by post.

Format of the tax number: Mein ELSTER requires the tax number in the standard scheme of the federal states. For Hesse, make sure the leading "0" is not forgotten. ELSTER shows a conversion table on its "Where is my tax number?" page.

Which number do you need when?

Returns and applications: under § 139a AO the taxpayer must state the identification feature assigned by the BZSt in applications, returns or notifications to the tax authorities. You do not have to hunt for the tax ID, though: the BZSt says you can also file your income tax return without the IdNr., because the tax office knows it or can find it out.

Invoice: the invoice shows the tax number issued by the tax office or the VAT ID issued by the BZSt (§ 14 (4) no. 2 UStG). For invoices up to €250 total, this information is not needed (§ 33 UStDV). This does not apply to invoices for supplies within the meaning of §§ 3c, 6a and 13b UStG.

VAT ID: it is issued by the BZSt. In the application you state your name, address and the tax number under which you are registered for VAT (§ 27a UStG). You can also apply in the tax registration questionnaire: the tax office forwards the application to the BZSt once you are registered for VAT.

OSS and other BZSt procedures: how registration at the BZSt works is explained in OSS registration in Germany: step by step. For the difference between tax number and VAT ID from an Amazon seller's point of view, see German tax number vs VAT ID: what Amazon sellers need.

What is the W-IdNr.?

The BZSt assigns every economically active person a business identification number without application, since November 2024 and in stages. It consists of the letters "DE" and a 9-digit sequence; for each individual economic activity a distinguishing feature is added, in general 00001 for the first one. The IdNr., the tax number and the VAT ID continue to be used alongside it. In the long term, after a transition phase, the W-IdNr. is meant to replace the tax number.

For you today: if you have not received a notice about a W-IdNr., the BZSt says this has no disadvantages. Stating it on tax return forms is optional until the first assignment is complete. Anyone who starts business activity and had no VAT ID by 30 November 2024, or starts a new activity, receives the W-IdNr. via the ELSTER mailbox. According to the BZSt (as of 10 September 2026), the W-IdNr. has been assigned since November 2024 first to everyone who must file an annual VAT return or is a small business owner (stage 1); corporation-tax payers and separate-determination cases follow from Q4 2026 (stage 2), everyone else from Q4 2027 (stage 3).

Which mistakes come up often?

Entering the tax ID as the tax number. ELSTER warns: the tax number is independent of the identification number.
Keeping the old tax number after a move. If the move changes your competent tax office, it generally issues a new tax number; the tax ID stays.
Assuming one tax number for all taxes. The tax office may issue a separate one for different taxes.
Treating the VAT ID as the tax number. The VAT ID comes from the BZSt, the tax number from the tax office; both are permitted on an invoice, but they are not the same.
Dropping the leading zero in Hesse. It belongs to the standard scheme of the federal states.
Waiting for the W-IdNr. Without a notice you have no disadvantages according to the BZSt; the tax number stays in use.

How VAT GPT helps you with this

Questionnaire: if you do not have a tax number yet, you fill in the tax registration questionnaire for sole proprietorships in VAT GPT.
Enter the tax number: if you already have it, you enter it in your personal details.
Tax ID: in the questionnaire, VAT GPT points out that the tax ID must not be confused with the tax number and explains where to find the tax ID.
Filing: with VAT GPT Pro you send the advance VAT return, OSS return, annual VAT return, EÜR, trade tax and income tax returns. Everything in one place.

There are Free (basic features, free of charge), Go (30 days free with all Pro features) and Pro (€49 per month or €444 per year), each including VAT. Try for Free Now

Frequently asked questions

Is the tax number the same as the tax ID? No. The tax office issues the tax number per case; the tax ID is an 11-digit number from the BZSt for the person. ELSTER calls them independent of each other.

Which number goes on my invoice? The tax number or the VAT ID (§ 14 (4) no. 2 UStG). The tax ID does not belong there.

Where do I find my tax ID? Usually on the income tax notice or the wage tax statement. Otherwise you request it again from the BZSt; it arrives by post.

Does my tax ID change when I move? No. According to the BZSt it does not change through a move.

Does my tax number change when I move? According to ELSTER, the competent tax office generally issues a new tax number after a move, when it announces its responsibility.

Is the tax number enough on my invoice? Yes, the invoice shows the tax number or the VAT ID (§ 14 (4) no. 2 UStG). Small business owners should also read: VAT return for a small business in Germany: do I have to file?.

What does the W-IdNr. change for me? Nothing binding today: without a notice you have no disadvantages, and the tax number is only to be replaced after a transition phase.