German Business ID Number (W-IdNr) 2026: What Founders and Self-Employed Must Know

Since November 2024, Germany's Federal Central Tax Office (BZSt) has been rolling out a new identifier to all economically active persons and businesses: the Wirtschafts-Identifikationsnummer (W-IdNr), or business ID number. By the end of 2026, every freelancer, self-employed person, UG and GmbH should have received their W-IdNr, automatically, without applying for it.

What does that mean for you? How does the W-IdNr differ from the Steuernummer, Steuer-ID and VAT ID (USt-IdNr)? Do you need to put it on invoices? Here's what you need to know.

In short

• What: a nationally uniform identifier for every business and every economic activity, set out in § 139c of the Fiscal Code (Abgabenordnung).
• Who: all economically active persons, including sole proprietors, freelancers, GbR, UG and GmbH, and small businesses under § 19 UStG.
• When: in phases since November 2024; the last businesses follow from Q4 2026.
• How: automatically, no application. Notified by post, by public announcement, or electronically via your ELSTER account.
• Cost: none. The W-IdNr is free.
• Does it replace anything? No. Your Steuernummer and VAT ID stay in place.

What is the W-IdNr, and why now?

The W-IdNr is a nationally uniform identifier for all economically active persons in Germany: sole proprietors, freelancers, partnerships and legal entities such as UG and GmbH. The legal basis is § 139c of the German Fiscal Code (Abgabenordnung).

The goal: tax authorities, statistical offices and other public bodies should be able to identify a business uniquely, across state lines and agency boundaries. This wasn't possible before, because the regular Steuernummer is state-specific and changes when you move to a different tax office. The W-IdNr, by contrast, stays the same for the life of the business, wherever it relocates.

The number is also a building block of Germany's administrative digitisation. In time it will feed the base register for business master data and simplify data exchange between authorities, the so-called once-only principle, where you supply master data to the state a single time.

Who gets a W-IdNr, and when?

The BZSt assigns the W-IdNr in phases, staggered by legal form and by which numbers you already hold. You don't need to apply, assignment is automatic.

If you already hold a VAT ID, you may have received your W-IdNr back in 2024 or 2025. If you're just starting out, you get it in the course of the tax registration questionnaire (Fragebogen) and the assignment of your Steuernummer.

What the W-IdNr looks like

The format: DE + 9 digits + hyphen + 5-digit suffix, for example DE123456789-00001.

For businesses that already hold a VAT ID, the first 11 characters of the W-IdNr match the VAT ID exactly, which keeps it readable. If you get the W-IdNr first and a VAT ID later, the two match numerically but are communicated to you separately.

The 5-digit suffix (Unterscheidungsmerkmal) is new. It starts at 00001 and lets multiple economic activities, business divisions or subsidiaries of one owner be identified separately. If you run, say, a photography business and an online shop, each activity can get its own marker (00001, 00002). The BZSt assigns these extra markers in stages from Q4 2027.

W-IdNr vs Steuernummer, Steuer-ID and VAT ID

Four numbers, four purposes, and from now on they coexist. This table shows which number does what:

The old Steuernummer stays, the W-IdNr does not replace it. If you run a GmbH or freelance practice with a VAT ID, you'll soon hold three to four numbers for different purposes. For more on the differences, see our guide to Steuernummer, Steuer-ID and VAT ID.

How do you find out your W-IdNr?

There are three ways the BZSt reaches you:

1. Public announcement. For most businesses with an existing VAT ID, the number was assigned not by individual letter but through a public announcement in the Federal Tax Gazette. In practice that means you have to retrieve the number yourself.
2. Electronically via ELSTER. Businesses that receive their W-IdNr electronically find it in the ELSTER user account under "Mein ELSTER". As a self-employed person you need an ELSTER account anyway for pre-registrations and returns.
3. By post. Those without a VAT ID receive the W-IdNr the classic way, by mail, in phases 2 and 3.

In every case there's no application and no fee. You either wait for the assignment to reach you or retrieve it in the portal.

What to do once you receive your W-IdNr

1. Keep it safe. When the BZSt letter or announcement arrives, scan the document and file it with your bookkeeping records. You'll need the number for future authority requests.
2. Update your master data. Add it to your accounting software, CRM and contract templates, wherever you currently store your Steuernummer or VAT ID.
3. Provide it on request. Authorities, Finanzämter and sometimes business clients will increasingly ask for the W-IdNr. It's becoming the standard business identifier in Germany.

Do you need to put the W-IdNr on invoices?

Currently: no. The mandatory invoice details under § 14 (4) German VAT Act still only require either the Steuernummer or the VAT ID, the W-IdNr is not mandatory. You can add it voluntarily, but you don't have to. For what actually belongs on an invoice, see our separate guide.

The W-IdNr also isn't yet asked for in the tax registration questionnaire (Fragebogen), but that will change as the tax administration gradually updates its forms over the next few years.

Data protection: who sees your W-IdNr?

The W-IdNr is not a publicly searchable register like the commercial register. The BZSt stores only the data listed exhaustively in § 139c AO, such as company name, legal form, address and economic sector. Access is limited to tax authorities acting within their remit. The data is retained for up to 20 years after the last economic activity ends and is subject to strict purpose limitation. For you that means you hand the number to authorities or contract partners deliberately, it is not published openly online.

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Frequently asked questions

Do I need to apply for the W-IdNr? No. The BZSt assigns it automatically, a separate application is neither necessary nor possible.

What does the W-IdNr cost? Nothing. Assignment and notification are free.

Do small businesses get a W-IdNr too? Yes. Small businesses under § 19 UStG are economically active and receive a W-IdNr as well, many already in Phase 1.

Does the W-IdNr replace my Steuernummer or VAT ID? No, not currently. All existing numbers stay valid and continue to be used. The W-IdNr is added on top.

Where do I find my W-IdNr if I've lost the letter? Via the ELSTER user account or the BZSt online portal, provided you've already been assigned one.

I have several activities. Do I get several W-IdNr? You keep the same 9-digit base number but get a separate 5-digit distinction marker (00001, 00002 …) for each economic activity. The BZSt assigns these extra markers from Q4 2027.

Conclusion

The Wirtschafts-Identifikationsnummer is a bureaucratic upgrade with no immediate operational impact, but it will become the standard ID for every business in Germany over the next few years. Adding the W-IdNr to your master data and bookkeeping early prevents last-minute scrambles when authorities ask for it.

With Norman, all your business identifiers and tax details sit in one place, from the Steuer-ID to the VAT ID and the new W-IdNr. So they're at hand for every invoice, every tax assessment and every GmbH tax filing.