Formats & standards
What is EN 16931? The European e-invoice standard explained
EN 16931 is the European standard at the heart of every EU e-invoicing mandate. A plain-language explanation of what it is (and isn't), how XRechnung, Peppol BIS and Factur-X all relate to it, and why it matters for compliance.
Last reviewed 2 June 2026
Every EU e-invoicing mandate points back to one thing: the European standard EN 16931. If your invoice complies with it, in an accepted format, it is a valid e-invoice across the EU. Here is what that standard actually is.
A data model, not a file format
EN 16931 is a semantic data model and a set of business rules, established under EU Directive 2014/55/EU. It defines what information a compliant e-invoice must contain and what each field means (the seller, the buyer, VAT identifiers, line items, the VAT breakdown, totals, and so on) and the rules they must satisfy.
Crucially, it is not itself a file format. It is the shared meaning that different file formats express. Think of it as the language; the formats below are dialects.
How the formats relate to it
EN 16931 is implemented in two XML syntaxes (UBL and CII) and through national or network-specific profiles called CIUS (Core Invoice Usage Specifications), which constrain the standard for a particular use.
XRechnung (Germany's public-sector format), Peppol BIS Billing 3.0 (used over the Peppol network), and Factur-X / ZUGFeRD (the hybrid PDF format) are all implementations of EN 16931. That is why an invoice can move between countries and systems and still be understood: underneath, they all speak EN 16931.
Why it matters for you
When a mandate says invoices must be "structured" or "compliant", it means compliant with EN 16931 in an accepted format. A plain PDF does not meet it, because the data is not present in a structured, machine-readable form.
You rarely need to read the standard yourself, your invoicing software handles it. What matters is choosing a tool that outputs a valid EN 16931 format for the country or network you are dealing with.
Frequently asked questions
Is EN 16931 a file format?
No. EN 16931 is a semantic data model and business rules (under Directive 2014/55/EU) that define what a compliant e-invoice must contain. It is expressed through file formats such as UBL, CII, XRechnung, Peppol BIS and Factur-X/ZUGFeRD.
What does an EN 16931-compliant invoice look like?
It is a structured, machine-readable invoice (XML, or a hybrid PDF with embedded XML) that contains all the mandatory fields and passes the standard's business rules. A plain PDF is not compliant on its own.
Is XRechnung the same as EN 16931?
XRechnung is a CIUS (a constrained profile) of EN 16931 for the German public sector. It is one implementation of the standard, not the standard itself. Peppol BIS and Factur-X are other implementations.
This guide is general information, not legal or tax advice. E-invoicing rules and dates change; always confirm the current position with the official source below or a qualified adviser before acting.
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