EN 16931: the standard every German e-invoice is built on

EN 16931 is not a file format. It describes which information an invoice carries and how it fits together — seller, buyer, lines, VAT, totals — as a list of numbered business terms: BT-1 is the invoice number, BT-5 the currency, BT-10 the buyer reference. On top come business rules that say what is mandatory and what has to agree with what.

Only the syntax turns that into a file. The standard permits two, UBL 2.1 and UN/CEFACT CII D16B, and fixes for both which XML element each business term goes in. An XRechnung in UBL and one in CII are therefore the same content in two spellings, and a ZUGFeRD PDF carries the CII one inside it.

It came out of Directive 2014/55/EU: public buyers in the EU have had to accept e-invoices under this standard since 2019 (central bodies) and 2020 (everyone else). German VAT law has built on it since 2025: an e-invoice under § 14 UStG conforms to the European standard and its list of syntaxes — or to a format the parties agree on that is interoperable with it.

In spring 2026 CEN adopted a new edition of part 1, EN 16931-1:2026. It replaces the 2017 edition with its 2019 amendment and, according to the European Commission, adds to the model what automated VAT reporting under ViDA needs. The German edition is DIN EN 16931-1:2026-10.

For an invoice you send today, that changes nothing yet. The Commission writes that the 2017 edition, though formally withdrawn, stays compliant during the migration period, and the migration plans are still being drawn up. CEN’s official validation rules (version 1.3.17 of October 2026) and XRechnung 3.0 are both built on the 2017 model.

Every invoice states which edition it was built against, in the specification identifier (BT-24): urn:cen.eu:en16931:2017. That is how it begins in every file our generator writes, the XRechnung included, whose identifier merely appends the usage specification.

The 2017 edition was free: the European Commission had agreed with CEN that parts 1 and 2 be given away “for the duration of the current version”. With the new edition that has ended until the agreement is renewed. DIN EN 16931-1:2026-10 costs DIN Media €366.20 as a German PDF at DIN Media (as of 25 October 2026). The syntax list, CEN/TS 16931-2, is still free.

For practical work you rarely need the text of the standard. KoSIT’s XRechnung specification restates the model with every business term, freely available, and the validation rules are open: CEN publishes its own as Schematron on GitHub, and our error index explains the rules evaluated in Germany in plain language.

The standard is deliberately broad. Countries and sectors may adapt it in two ways, and the invoice says in BT-24 which one was chosen.

Core invoice usage specification (CIUS)

Restricts and clarifies without adding anything: every invoice under the CIUS is also a valid invoice under the standard. XRechnung is one, as is Peppol BIS Billing 3.0. Identifier: urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0

Extension

Adds fields the standard does not know, and is therefore only “conformant”, not “compliant”. ZUGFeRD EXTENDED is the best-known example — why an authority refuses it is on the page ZUGFeRD Extended or XRechnung.

With Directive (EU) 2025/516 (“VAT in the Digital Age”, in force since 14 April 2025) the standard goes from the standard for invoices to public bodies to the standard for everyone. Since then member states may require e-invoicing at home without a derogation. From 1 July 2030 e-invoices must in principle conform to EN 16931 and its list of syntaxes — states may allow other formats for domestic supplies — and digital reporting begins for business-to-business supplies between EU countries.