If you work for yourself in Germany, you will encounter several numbers with similar names. An income tax assessment shows a Steuernummer, a letter from the Federal Central Tax Office contains your personal Steuer-ID, and business dealings with companies in other EU countries often involve an Umsatzsteuer-ID. These identifiers serve different purposes and are not interchangeable.
This guide explains which number you need, where to find it and which one belongs on an invoice. It covers German tax law, including the business identification number and the special rules for small businesses.
The three numbers at a glance
- Steuernummer — tax number: Your local tax office uses it to identify a tax case. Individuals, self-employed people and companies can all have one. It may change when responsibility moves to another tax office.
- Steuer-ID or IdNr. — personal tax identification number: The Federal Central Tax Office (BZSt) issues this eleven-digit number to individuals. It stays with you for life, including after moving, marrying or switching between employment and self-employment.
- Umsatzsteuer-ID or USt-IdNr. — VAT identification number: This additional BZSt identifier is particularly relevant to VAT procedures within the EU single market. A German VAT ID consists of “DE” followed by nine digits.
Remember the distinction: tax case — individual — VAT identification in EU business. Your personal tax ID is not a VAT ID. Even an eleven-digit Steuernummer does not become a personal IdNr. because of its length; check the label on the official document.
Steuernummer: identifying your case at the tax office
You can find this number on tax assessments and correspondence from your Finanzamt. It is not reserved for commercial businesses or legal entities. Employees, independent professionals and other individuals can also have one. Several tax numbers may exist alongside each other for different procedures or responsibilities.
When starting a business, you generally submit the tax registration questionnaire through ELSTER. The tax office checks your information and notifies you of the number relevant to your business. An existing income tax number is not automatically suitable for every business invoice. If you have several numbers, ask the tax office which applies to the business and its VAT matters.
Formats vary between German states and often contain slashes. There is also a standard thirteen-digit format for electronic procedures. Copy the number from the correct document and follow the specific form's input guidance. Do not remove or add digits by guesswork.
Steuer-ID: your personal number
The personal tax identification number identifies you as an individual. It is used, for example, for income tax and payroll tax withholding. Look for it in the original BZSt notification, your income tax assessment or your annual payroll tax certificate. If you cannot find it, request another notification from the BZSt. This retrieves your existing number; it does not create a new one.
For newcomers to Germany, the distinction is especially useful: a foreign tax identifier is not automatically the German IdNr. First registration of residence in Germany normally initiates allocation. Special cases involving people without German residence are handled through the responsible tax authorities.
Do not put your personal Steuer-ID on an outgoing invoice instead of a Steuernummer or VAT ID. Share it only where it is required for a specific permitted purpose. A customer normally does not need your personal IdNr. to pay for your services.
VAT ID: an additional identifier for EU business
The BZSt issues the USt-IdNr. on application. You can request it in your tax registration questionnaire when setting up a business or use the relevant BZSt procedure. The tax office must have registered your business for tax purposes. Trade registration alone does not replace that step.
The number is particularly relevant to certain supplies of goods and services between businesses in different EU member states. This does not mean every international invoice requires a German VAT ID, or that an invoice showing two VAT IDs is automatically tax-exempt. The type and place of supply, the customer's business status and the conditions applying to the transaction all matter.
Check another EU country's VAT IDs through the official BZSt confirmation procedure or the European Commission's VIES service, and retain the result. A valid number is an important check, but it does not determine the full tax treatment. Small businesses can also obtain a VAT ID. Allocation alone does not waive the German VAT exemption scheme for small businesses (Kleinunternehmerregelung); cross-border purchases can nevertheless create separate VAT obligations.
Which number belongs on an invoice?
A standard domestic invoice
Under section 14(4), sentence 1, number 2 UStG, a standard invoice must include the supplier's Steuernummer or VAT ID. In an ordinary domestic case, you do not need both. Using a valid VAT ID therefore means you do not also need to disclose your Steuernummer for this requirement. Neither the personal tax ID nor the business identification number replaces it.
The number is only one part of the invoice. Other mandatory particulars include full names and addresses, issue date, a sequential invoice number, a description and date of supply, and the appropriate amounts and tax details. A correct identifier does not make an otherwise incomplete invoice compliant.
An invoice under the small-business exemption
Transactions exempt under section 19(1) UStG have specific minimum invoice requirements in section 34a UStDV. These include both parties' names and addresses, issue date, description of supply, total consideration and a reference to the small-business VAT exemption. The permitted identifier is a Steuernummer, VAT ID or small-business identification number.
The small-business identification number belongs to the special EU procedure. It is neither your personal tax ID nor your business identification number. If you do not use that procedure and have no such identifier, your relevant Steuernummer is sufficient for the normal domestic small-business case. Do not show VAT separately on a transaction exempt under section 19. A commercial trade and small-business status are not alternatives: one describes the activity, while the other is a VAT scheme that independent professionals may also use.
Small amounts and special EU cases
Section 33 UStDV allows simplified invoices up to €250 in total; a Steuernummer or VAT ID is not among their minimum particulars. However, the simplification does not apply to transactions under sections 3c, 6a and 13b UStG. “Below €250” is therefore not a universal exception.
Section 14a UStG requires additional information for certain cross-border EU transactions, such as both businesses' VAT IDs and, for relevant services, a statement that the recipient owes the tax. Establish the actual tax treatment before adding “tax-exempt” or “reverse charge” to a template.
What is the business identification number?
The Wirtschafts-Identifikationsnummer, or W-IdNr., is another identifier for economically active persons and entities. The BZSt began allocating it in stages in November 2024 without requiring an application. Its structure includes “DE”, nine digits and a further five-digit distinguishing suffix, such as “-00001”.
Its similarity to a VAT ID can be confusing. A W-IdNr. does not replace a required VAT ID or the separate application for one. Do not simply copy it into your invoicing software's VAT ID field. Check the exact name on the notification and manage the two identifiers separately. Your personal IdNr. also continues to exist.
How to proceed when starting a business
- Organise existing documents: Keep your personal IdNr., previous tax assessments and business correspondence separately. Record the issuing authority and purpose for each number.
- Complete tax registration: Generally submit the relevant ELSTER questionnaire within one month of opening the business or starting an independent professional activity. Trade registration does not replace the questionnaire.
- Clarify VAT treatment: Consider ordinary VAT taxation or the small-business exemption and any planned foreign transactions. Apply for a VAT ID early where needed; do not assume a guaranteed processing time.
- Check the official allocation: Compare the name, address and number with your business records. Ask the tax office or BZSt about discrepancies.
- Check your invoice template: Enter the correct identifier in its designated field and review the entire generated invoice before sending it.
If a required number has not arrived, do not invent one or substitute your personal tax ID. Writing “tax number applied for” does not satisfy the identifier requirement. Ask the tax office or a tax adviser how to issue or complete the invoice correctly and on time; a later correction may be necessary.
Three everyday examples
A cleaning business invoices a domestic customer
A business subject to ordinary VAT taxation charges a German business customer €600 plus VAT. For the number requirement discussed here, its business Steuernummer or VAT ID is generally sufficient. The owner's personal tax ID does not belong in that field. All other mandatory invoice particulars remain necessary.
A freelance designer uses the small-business exemption
She charges a German customer €700 for design work covered by her section 19 exemption. She uses her business Steuernummer and a statement referring to the small-business VAT exemption. This domestic invoice alone does not require a VAT ID. If she also has a VAT ID, that does not automatically remove her small-business status.
A consultant works for a French business
For an ordinary B2B consultancy service supplied to a French business, the place of supply may be France and the customer may owe the tax there. The relevant VAT IDs and reverse-charge statement must then be checked; a recapitulative statement may also be relevant. Special rules, such as those for property-related services, can produce a different result. The customer's residence alone is not enough to decide.
Common questions and important corrections
Does my number change when I move?
Your personal tax ID stays the same. A Steuernummer may change if another tax office becomes responsible. Update your business and invoicing data based on the official notification and tell the responsible authorities about changes.
Does having a VAT ID mean I must always charge VAT?
No. An identifier and a transaction's tax treatment are separate matters. Exemptions, the small-business scheme, place of supply and any transfer of tax liability to the recipient must be checked individually.
Does having a particular number automatically require e-invoices?
No. The required invoice format depends on the transaction and legislation, not simply on having a VAT ID. New rules have applied to domestic B2B transactions since 2025, with transitional periods: other invoice formats can generally still be used until the end of 2026. Electronic non-structured invoices, such as a simple PDF, require the relevant recipient consent. Small businesses are exempt from issuing e-invoices but must be able to receive them. Public-sector customers may have their own requirements.
Must invoices always be retained for ten years?
Under section 14b UStG, the general VAT retention period for businesses is eight years, starting at the end of the year of issue. An invoice issued in 2026 must therefore generally be retained until 31 December 2034. Other legislation or ongoing tax proceedings may require longer retention. The obligation applies whether or not an audit has been announced.
Checklist for your next invoice
- The identifier belongs to the correct business and tax case.
- Personal tax ID, Steuernummer, VAT ID and W-IdNr. are recorded separately.
- The invoice type and relevant mandatory particulars are clear.
- Small-business exemption or other tax statements match the actual transaction.
- For EU business, customer status, place of supply and any required VAT ID have been checked.
- Name, address and number match the official documents.
- The invoice and relevant supporting evidence are stored systematically.
Motorica.io helps you organise business details, invoices and accounting documents or receipts. Label your identifiers clearly and preview an invoice after each change. The software does not issue official tax numbers or determine the tax treatment of your transactions.
This article provides general guidance on German tax law. For unusual cross-border situations, several businesses or unclear VAT treatment, discuss your particular circumstances with a qualified tax adviser.
Official sources and further information
- BZSt · IdNr.
- ELSTER
- ELSTER · Steuernummer
- BZSt · USt-IdNr.
- VIES
- BMF · W-IdNr.
- BMF · E-Rechnung
- UStG § 14
- UStG § 14a
- UStG § 14b
- UStG § 19
- UStG § 19a
- UStG § 27a
- UStDV § 33
- UStDV § 34a
- AO § 138
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