What is EN 16931? Electronic Invoicing Standard in Germany

EN 16931 is the European standard for electronic invoicing that defines a common, structured data model, enabling uniform, cross-border, and machine-readable e-invoices. It ensures legal validity, automation, and interoperability across all EU member states. Based on this standard, Germany developed its own e-invoicing format called XRechnung.

Key Takeaways

• EU-wide standard ensuring structured, consistent electronic invoicing for businesses and governments.
• EN 16931 defines a core invoice data model that covers supplier, buyer, tax, and payment details.
• Supports XML syntaxes: UBL 2.1 and UN/CEFACT CII for compatibility across systems.
• Allows national adaptations like Germany’s XRechnung and ZUGFeRD formats..
• EN 16931 enables automation, faster processing, reduced errors, and easier VAT compliance under EU’s digital tax reforms.

What is EN 16931 Standard in Germany?

EN 16931 standard establishes the required and optional elements of an invoice that must be contained in an electronic invoice. These involve supplier and buyer information, invoice number, tax and line items and payment instructions. It aims in ensuring that e-invoices are compatible with the EU so that an invoice issued in one country would be processed in another through the machine without manual modifications.

At its core, EN 16931 is like a “universal language” for electronic invoices across Europe. Imagine you and your supplier speak different languages, your accounting system says “Invoice Date,” theirs says “Billing Date.” 

EN 16931 steps in and says: “Let’s all agree to call it Invoice Issue Date, and here’s how it must be written and structured in the file.”

So instead of everyone creating their own way of listing invoice details, EN 16931 defines a standardized set of data fields and meanings like the sender’s name, buyer’s VAT number, invoice number, prices, taxes, and payment details so that every computer system across the EU can read and understand it without confusion.

EU & German E-Invoicing Mandate for Structured Data

E-invoicing is the digital exchange of invoices in a structured, machine-readable format (such as XML or UBL), enabling automated processing and compliance with tax and reporting laws. It requires invoices to include standardized data fields like supplier, buyer, VAT details, and totals so they can be validated and exchanged seamlessly between systems and countries.

Across Europe, governments are replacing paper and PDF invoices with structured, machine-readable e-invoices to fight VAT fraud and cut administrative costs. In Germany, starting January 2025 all B2B invoices between German-established businesses must be electronic and EN 16931-compliant (phased in fully by 2028).

Why “Structured Data” Matters

A structured e-invoice stores information as defined data fields like seller VAT ID, invoice date, taxable amounts, tax rate, payment terms—inside an XML file rather than free text. Software can read, validate, and post this data automatically, eliminating manual entry and transcription errors.

Interoperability on a Shared Protocol

EN 16931 acts as Europe’s interoperability backbone. It defines a standard semantic model and maps it to universally accepted syntaxes. Because every compliant invoice uses the same structure and code lists (currency, VAT category, country codes), any EU-approved platform, Germany’s ZRE/OZG-RE portals, France’s Chorus Pro, or the Peppol network can exchange and interpret it without conversion.

This shared protocol ensures that:

• An invoice issued in Germany can be processed in France or Italy without format changes.
• Businesses use one data model for all public-sector and, increasingly, B2B invoicing.
• Tax authorities gain a consistent dataset for digital VAT reporting under the EU’s upcoming VAT in the Digital Age (ViDA) reforms.

Features of EN 16931

EN 16931 defines a structured data model and strict validation rules to maintain consistency and accuracy in electronic invoices across the EU.

1. Core Data Model: 

The standard specifies a Core Invoice Data Model (EN 16931-1) that includes all essential invoice elements such as seller and buyer details, VAT ID, invoice number, date, line item descriptions, quantities, prices, tax rates, totals, and payment terms. This ensures each invoice includes the minimum information required for accounting and tax compliance in every EU country.

2. Validation Rules: 

The standard enforces mathematical and logical consistency. Totals must equal the sum of line items, tax values must match taxable amounts and rates, and standardized codes must be used for currencies, countries, and tax categories. These checks ensure accuracy and allow automated validation and processing.

3. Syntax Independence with Mappings: 

EN 16931 defines data requirements independently of any specific format. It maps the data model to two recognized XML syntaxes:

• UBL (Universal Business Language) 2.1
• UN/CEFACT Cross Industry Invoice (CII)

Countries and industries can use either syntax while maintaining interoperability. Peppol BIS 3.0 applies UBL, and ZUGFeRD/Factur-X uses a PDF file with embedded CII XML. Both follow EN 16931 rules.

4. Extensibility – CIUS and Extensions:  

The standard allows localized adaptations through Core Invoice Usage Specifications (CIUS). A CIUS refines the core model for specific national or sector needs without breaking compatibility. Germany’s XRechnung is a CIUS that adds routing fields for public sector invoicing. Extensions can include extra optional data agreed upon between trading partners, provided they do not alter mandatory elements.

5. Interoperability and Automation:  

Invoices built on the EN 16931 structure can be processed by any compliant system across the EU. This enables interoperability, supports automation, and removes manual data entry. Automated matching, validation, and posting of invoices reduce time, cost, and errors while improving operational efficiency.

Core Elements of EN 16931 in Germany

The EN 16931 norm defines mandatory invoice components that ensure completeness and clarity.

EN 16931 Format and Examples in Germany

EN 16931 does not dictate one single file format. Instead, it defines what information an electronic invoice must contain and how that information should be structured. To make this work in practice, the European Commission recognizes a few standard file types that can carry this data.

1. UBL (Universal Business Language):

UBL is a common file format used across Europe for exchanging business documents such as invoices and purchase orders. When an invoice follows the UBL layout and includes all EN 16931 data fields—like invoice number, date, seller, buyer, prices, and taxes—it becomes EN 16931 compliant. In simple terms, a UBL invoice is a structured XML file (ending in .xml or .ubl) that software can easily read and process automatically. The Peppol e-invoicing network uses this UBL-based format.

2. UN/CEFACT Cross Industry Invoice (CII):

This is another XML format developed by the United Nations. It contains the same kind of structured information but follows a slightly different layout. In Germany, the ZUGFeRD format uses this CII XML data, but adds a convenient twist—embedding the XML file inside a regular PDF. This means a person can open and view the invoice as a normal PDF, while accounting software can read the structured XML data hidden inside it.

Example

Imagine you receive an invoice from a supplier. You can either:

• Open it like a normal PDF to see the company name, invoice date, and total amount, or
• Let your accounting software automatically read the XML data inside the same file to post it into your books.

Both the PDF (for humans) and XML (for software) show the same information. This makes the process smoother, faster, and compliant with European invoicing standards.

How EN 16931 is Implemented in Germany

Germany applies EN 16931 as the foundation of its e-invoicing system. The two main formats used, XRechnung and ZUGFeRD, both follow the EN 16931 data model.

B2G Invoicing (XRechnung):  Since 2020, all suppliers sending invoices to German government bodies must use the XRechnung format. 

B2B Invoicing Mandate (2025 Onwards):  From 1 January 2025, EN 16931 compliance will also apply to B2B transactions. All invoices exchanged between German businesses must be issued in an EN 16931-compliant structured format, such as XRechnung (XML) or ZUGFeRD (PDF plus XML). Simple PDFs or paper invoices will no longer qualify as valid electronic invoices, except during a limited transition phase or when both parties agree otherwise.

Allowable Formats: Invoices must either conform directly to EN 16931 or use another structured format both parties agree upon, provided it can be mapped to the EN 16931 data model. Common compliant options include XRechnung, ZUGFeRD, and Peppol BIS 3.0 (UBL format).

Infrastructure: Germany supports EN 16931 implementation through:

• ZRE and OZG-RE portals for submitting government invoices
• Peppol network access, enabling standardized cross-border e-invoicing

XRechnung vs. EN 16931

EN 16931 is the documentation of electronic invoicing in the EU, whereas XRechnung is a national implementation of this documentation in Germany. The EN 16931 norm establishes the general rules and XRechnung uses it with national adjustments in order to comply with the needs of the German government and tax authority.

In Layman's terms

Think of EN 16931 as a recipe book for making a standard European invoice. It lists the ingredients (data fields like seller name, invoice date, VAT, and totals) and the steps (how the data should be structured) so that anyone in Europe can make a compliant “invoice dish.”

Now, XRechnung is like Germany’s local version of that recipe. It takes the same ingredients from EN 16931 but adds local seasoning, a few extra steps and ingredients that the German government requires, such as the Leitweg-ID (a routing code for public offices).

So if EN 16931 says, “Every invoice must have flour, sugar, and butter,” XRechnung says, “Yes, and in Germany, you must also add a pinch of salt and bake it at our local temperature.”

In other words:

• EN 16931 = The European e-invoice recipe everyone must follow.
• XRechnung = The German version of that recipe, customized to meet local rules.

Who Must Comply with EN 16931 Standard in Germany?

Germany is introducing e-invoicing rules based on the EN 16931 standard to standardize and digitize invoicing across both public and private sectors. Compliance depends on who the invoice is issued to and the transaction type.

1. Public Sector Suppliers (B2G):  

Suppliers invoicing federal or state authorities must send EN 16931-compliant invoices, mainly in XRechnung format. This has been mandatory since November 2020 for invoices over €1,000, submitted through the ZRE or OZG-RE portals.

2. Private Businesses (B2B): 

• From 1 January 2025, all VAT-registered businesses must be able to receive e-invoices in EN 16931 format.
• From 1 January 2027, companies with turnover above €800,000 must issue only structured e-invoices.
• From 1 January 2028, the rule applies to all businesses, regardless of size.

3. Transitional Arrangements: 

Between 2025 and 2027, PDF or paper invoices may still be used if both parties agree. Existing EDI systems can continue if they include all EN 16931-required data elements.

4. Exemptions:  

Invoices under €250, small businesses under §19 UStG, transport tickets, parking receipts, and certain B2C or real-estate-related services are exempt.

Benefits of Adopting the EN 16931 Standard

Adopting the EN 16931 standard helps German businesses modernize their invoicing process, meet legal requirements, and improve operational efficiency. It provides a unified digital framework that enhances accuracy, speed, and compliance across the EU.

1. Regulatory Compliance: Ensures all invoices meet EU Directive 2014/55/EU and Germany’s e-invoicing laws for B2G and B2B transactions, minimizing the risk of non-compliance penalties.
2. Operational Efficiency: Automates invoice creation and processing, reduces manual work, and lowers costs associated with paper, postage, and administrative errors.
3. Faster Payments: Structured, machine-readable invoices allow faster validation and payment processing, improving cash flow and reducing outstanding receivables.
4. Audit & Tax Readiness: Provides standardized invoice data for easier VAT validation, error detection, and compliance with upcoming real-time reporting systems.
5. Interoperability Across Europe: Guarantees smooth exchange of e-invoices between systems and countries, ensuring compatibility with formats like XRechnung, ZUGFeRD, and Peppol BIS 3.0.

Conclusion

The European electronic invoicing standard is EN 16931. Businesses can be compliant, efficient and interoperable by using the formats, like EN 16931 XRechnung, ZUGFeRD or Peppol BIS. With the B2B e-invoicing requirement coming into effect in 2025 in Germany, E-Rechnung EN 16931 adoption is no longer discretionary, but a necessity to ensure digital compliance in future.