Mandatory Data Fields Required for an e-Invoice in Germany

Germany’s e-invoicing obligations makes an invoice valid only when mandatory VAT data is delivered as structured, machine-readable content aligned to EN 16931. Reception capability for structured e-invoices applies from January 1, 2025; domestic B2B issuance becomes mandatory from January 1, 2027 (larger enterprises) and January 1, 2028 (all).

Key takeaways

• Mandatory content follows §14 UStG: seller/buyer IDs and addresses, invoice number, issue and supply dates, line description, quantity/unit, net amounts, VAT rate/category, VAT totals, and amount due.
• Encode these values using EN 16931 Business Terms (BT codes) for consistent validation and processing across systems.
• Use a compliant format such as XRechnung (XML) or ZUGFeRD 2.0.1+, and include currency plus payment terms.
• XRechnung adds mandatory process and endpoint fields (e.g., ProfileID, EndpointIDs) and, for B2G, the Leitweg ID; missing fields commonly trigger rejection and payment delays.

Germany’s E-Invoicing Mandate

Germany is moving B2B invoicing from “documents” to structured, machine readable data. An invoice qualifies as an e-invoice only when it is issued in a structured format that can be automatically processed by the recipient’s systems, typically using EN 16931 compliant standards such as XRechnung or ZUGFeRD.

The mandate requires businesses to be able to receive structured e-invoices first, then to issue them for domestic B2B transactions in phases. The timeline below shows how the implementation is staged.

What Are the Mandatory Fields of an e-Invoice in Germany?

Every e-Invoice in Germany should be issued with Mandatory data fields - the minimum legal and technical dataset, which makes an e-invoice valid, processable, and auditable, like seller and buyer identifiers, invoice number, issue and supply dates, item level quantities, etc. 

In Germany, mandatory e-invoice fields are the legally required VAT invoice details under §14 UStG, carried in structured EN 16931 Business Terms, plus any additional mandatory fields imposed by the chosen German format, such as XRechnung.

• §14 UStG defines what information must appear on an invoice for VAT purposes in Germany. This includes the parties’ identification, a unique invoice number, issue and supply or service dates, a clear description of goods or services, quantities, net amounts, VAT rate and VAT amount, and the total amount payable.
• EN 16931 defines how that same legally required information must be expressed as structured, standardized data so the invoice can be validated and processed automatically. EN 16931 describes invoice content using Business Terms, commonly shown as BT codes. 

Note: A BT code represents one specific data field with a fixed meaning, such as invoice number, seller name, buyer name, line net amount, total VAT amount, or amount due. This standardization ensures the field is interpreted consistently across systems and across formats like XRechnung or ZUGFeRD.

General Mandatory Fields Under §14 UStG

According to §14 of the German VAT Act (UStG), the following fields must appear on an invoice so it is VAT-compliant and can be used to support correct VAT reporting and input VAT deduction.

Special Case: Small-Value Invoices Under €250

Small-value invoices for domestic B2C transactions can follow simplified requirements, while still needing structured data if issued as an electronic invoice.

The simplified content set typically includes:

• Seller name and address
• Invoice issue date
• Description of goods or services
• Quantity and unit
• Total amount including VAT

EN 16931 Mandatory Business Terms for Structured e-Invoices

EN 16931 is the European e-invoicing standard that defines a common “meaning layer” for invoice data so different systems interpret the same fields consistently. Instead of describing an invoice as free text, EN 16931 defines a semantic data model made up of two building blocks

• Business Terms (BT): A Business Term (BT) is one specific data element with a fixed definition. Think of a BT as a single “field” that must be captured in a structured invoice, such as: Invoice number, Invoice issue date, etc.  Because every BT has a standard meaning, an ERP system can validate and process the invoice without guessing what a value represents.
• Business Groups (BG): A Business Group (BG) is a logical container that bundles related Business Terms together. For example: A “Seller” group can contain seller name, address, and tax identifiers. BGs help structure the invoice into consistent sections, especially when the same type of information repeats

BT Cardinality: Mandatory, Conditional, or Optional Fields

Each BT is defined with cardinality, which tells you how many times the field may appear in a valid invoice, and whether it must appear at all.

• 1..1 means the field is mandatory and must appear exactly once (Example: Invoice number should exist once, not zero times, not twice)
• 0..1 means the field is optional and may appear once or not at all (Example: A buyer reference might be used only in certain business flows)
• 1..n means the field is mandatory and repeatable (Example: Invoice lines must appear at least once and can appear many times)
• 0..n means the field is optional and repeatable (Example: Supporting references can be added multiple times if relevant)

Core Document-Level Mandatory BT Fields

The table below lists common EN 16931 document-level elements that are mandatory in a compliant invoice instance.

Mandatory Line-Level and Financial BT Fields

Mandatory line and totals data ensures that the invoice is mathematically consistent and can be automatically posted.

XRechnung-Specific Mandatory Fields

XRechnung is Germany’s national implementation of EN 16931 and introduces additional mandatory fields that support routing and consistent processing in the German ecosystem.

The following fields are mandatory in XRechnung 3.0.1 and later, and B2G invoices may require additional routing references.

Mandatory Field Requirements by Invoice Type

Invoice type changes do not reduce the baseline mandatory fields. They change which references, codes, and narrative markers must be present so the invoice is posted correctly.

Why Mandatory Data Fields Important?

Mandatory data fields are not a formatting preference. They are the minimum information set that allows an e-invoice to be legally valid under German VAT rules, technically valid under EN 16931, and automatically processable by the buyer’s ERP and accounts payable systems.

• VAT Compliance: The mandatory fields evidence who supplied what, when, at what value, and how VAT was treated, which underpins correct VAT reporting and input VAT deduction.
• Automated Processing: EN 16931 Business Terms enable consistent parsing across platforms, so the buyer can automatically match invoices to purchase orders, goods receipts, and contracts.
• Dispute Prevention: Clear quantities, unit measures, and VAT calculations reduce rejection, credit note churn, and payment delays triggered by data inconsistencies or missing fields.
• Integrity and Evidential Value: Authenticity of origin, integrity of content, and readability are explicit requirements for invoice reliability. They protect both parties if a transaction is challenged.

Practical Validation Rules to Avoid Rejections

A structured e-invoice can fail even when the business deal is correct, because the data does not pass technical or arithmetic validation. The checks below help prevent avoidable rework and payment delays.

• Uniqueness and Reference Controls: Ensure invoice numbers are unique and consecutive, and that credit notes and corrections reference the correct original invoice.
• Date Consistency: Keep issue dates, supply dates, and service periods consistent with the transaction and with the invoice type. Use structured date formats consistently.
• Mathematical Consistency: Reconcile line totals to document totals. Net totals plus VAT totals should match the gross total, and VAT totals should match VAT rates and taxable bases.
• Mandatory Field Presence by Profile: If you are issuing XRechnung, validate the presence of BT-23, BT-34, and BT-49, and include the Leitweg ID in BT-10 for federal B2G recipients.
• Integrity and Readability Controls: Apply controls that ensure authenticity, integrity, and readability across the invoice lifecycle, including issuance, transmission, and archiving.

Conclusion

Mandatory e-invoice fields are the intersection of VAT defensibility and operational efficiency. Treat them as a data quality program, not a checklist. Build a single mapping that satisfies §14 UStG and EN 16931, validate it early, and enforce it consistently so invoices flow through buyer systems without rejection.