What is EN 16931?

The EN 16931 standard establishes the foundation for a standardized electronic invoice format, thereby simplifying the process for companies issuing cross-border invoices.

Introduction to the European Invoice Standard EN 16931

EU Directive EN 16931: Standardized compliance in electronic invoicing

Published on June 28, 2017, the EN 16931 standard represents a significant step in the European initiative to standardize electronic invoicing. This standard defines a uniform format for cross-border invoicing and specifies how an electronic invoice should be structured for international transactions. It outlines the core terminology and format for digital invoicing while also allowing additional country-specific and industry-specific extensions, known as Core Invoice Usage Specifications (CIUS), to meet local requirements.

This standard is particularly relevant for companies working with public sector clients, but its impact extends across the entire economy. EN 16931 implements the European directive on compliance requirements for electronic invoicing in public procurement (EN 2014/55/EU) and mandates that, from 2020 onward, invoices to public authorities must be sent electronically. This shift to electronic invoicing solutions helps streamline invoice processing and ensures cross-border consistency.

Who is affected & legal framework

Since January 1, 2025, there has been a legal obligation to receive EN 16931-compliant e-invoices for all domestic B2B transactions.

The issuance of e-invoices is being implemented in phased stages:

• Until December 31, 2026: Paper invoices and PDF invoices (with recipient consent) are still permitted
• January 1, 2027: Mandatory issuance for companies with prior-year revenue > €800,000
• From January 1, 2028: Full mandatory adoption for all companies in the B2B sector to use EN 16931 e-invoices—without exceptions (except EDI, if fully extractable).

Which formats are permitted?

• XRechnung: A purely machine-readable XML invoice for public authorities (Germany).
• ZUGFeRD from version 2.0.1: A hybrid format (PDF/A-3 + XML) with EN 16931 profile and optional XRechnung integration.

Other structured formats such as EDI are permitted, provided they deliver fully extractable datasets in accordance with VAT legislation.

What obligations arise for companies?

1. Since January 2025: Every domestic invoice recipient must be able to receive e-invoices.
2. From 2027/2028: Invoice issuers must send e-invoices themselves (depending on revenue class).
3. Recipient consent is no longer required for receiving invoices since 2025—exceptions only apply for B2C or tax-exempt/low-value cases (< €250).

What are the Core Invoice Usage Specifications (CIUS) in EN 16931?

The Core Invoice Usage Specifications (CIUS) in EN 16931 are comprehensive, tailored guidelines that describe in detail how the core elements of an invoice are to be used. EN 16931 provides the foundational framework and data model for the core invoice, while CIUS further refines these elements. CIUS defines specific requirements for creating invoices in different contexts, such as various industries or sectors. It ensures consistency and clarity in invoicing.

What are the benefits of complying with EN 16931?

EN 16931 is more than just a European standard—it is a transformative development for the cross-border exchange of invoices. This directive lays the groundwork for a standardized electronic invoicing format, simplifying the process for companies issuing cross-border invoices.

The EN 16931 standard facilitates the adoption of e-invoicing software and supports invoice automation, increasing the efficiency of invoice processing systems. Its adaptability through CIUS helps businesses meet both B2B e-invoicing requirements and industry-specific needs, ensuring seamless integration and improved invoicing accuracy. As regulations across Europe continue to tighten, companies that must ensure global e-invoicing compliance increasingly view TrueCommerce as the ideal technology partner to navigate these complex transitions. Understanding and implementing EN 16931 is critical for businesses aiming to optimize invoicing practices and remain competitive in the global market.

Overview of transition periods

Key takeaways:

• EN 16931 is an EU directive that standardizes electronic invoicing to ensure tax compliance across Europe.
• Compliance with EN 16931 is essential for UK companies trading with EU member states.
• The Core Invoice Usage Specifications (CIUS) in EN 16931 provide detailed guidance on how invoice core elements should be used.
• EN 16931 is critical for businesses to remain competitive in the global market.