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.

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.

Who gets a W-IdNr — and when?

The BZSt assigns the W-IdNr in phases, staggered by legal form and industry:

• Phase 1 (since November 2024): Businesses that already held a VAT ID (USt-IdNr).
• Phase 2 (2025–2026): All other economically active persons — including freelancers without a VAT ID.
• Phase 3 (expected Q4 2026): Remaining sole proprietors registered with their local Finanzamt.

You don't need to apply — the W-IdNr is assigned automatically and sent by post. Businesses with a VAT ID can also retrieve theirs via the BZSt's online portal.

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. The 5-digit suffix (Unterscheidungsmerkmal) is new and allows multiple branches or subsidiaries of one business to be identified separately.

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

Four numbers, four purposes:

• Steuer-ID: Every natural person in Germany — personal taxes (income tax, payroll).
• Steuernummer: Anyone registered with a Finanzamt — tax assessments, EÜR, VAT returns.
• USt-IdNr (VAT ID): Businesses trading inside the EU — EU B2B invoicing and EC Sales List.
• W-IdNr: All economically active persons — cross-agency identification at federal level.

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 numbers for different purposes. For more on the differences, see our guide to Steuernummer, Steuer-ID and VAT ID.

What to do once you receive your W-IdNr

1. Keep it safe. When the BZSt letter arrives, scan it 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.

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.

What if you lose your W-IdNr?

Not a problem. You can retrieve it any time via the BZSt's online portal, provided you've already been issued one. If the letter hasn't arrived yet, there's no application: the BZSt sends them out automatically on a fixed schedule.

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.