EN 16931: what makes an electronic invoice compliant

The EU asked for it in Directive 2014/55/EU on electronic invoicing in public procurement, which defines an electronic invoice as one

and rules out the simplest case in its recitals:

A PDF sent by e-mail, however neat, is therefore not an electronic invoice in this sense. The standard itself was issued by the European Committee for Standardisation (CEN) on 28 June 2017, and its reference published in the Official Journal by Commission Implementing Decision (EU) 2017/1870, Article 1, in two parts:

• EN 16931-1:2017, Electronic invoicing, Part 1: Semantic data model of the core elements of an electronic invoice;
• CEN/TS 16931-2:2017, Electronic invoicing, Part 2: List of syntaxes that comply with EN 16931-1.

The semantic data model

The heart of the standard is a list of the information an invoice carries, what each item means, and the rules between them. It does not say how the file is laid out:

The two syntaxes

Commission Implementing Decision (EU) 2017/1870, Annex.

A public buyer in the EU has to accept an invoice in either of the two, as the section on who must accept it shows below.

A country or a sector often needs more precision than the core model, or more data. The standard provides two tools for that, and they are not equally compliant:

• A CIUS (Core Invoice Usage Specification) narrows the core, for example by restricting how its items may be filled in. It stays inside the standard.
• An extension adds items the core does not have. It leaves the standard.

The German XRechnung is a worked example of both. Its publisher describes it as a CIUS and an extension together:

Which German format to send to which recipient is a separate, practical question, answered in German on XRechnung oder ZUGFeRD?

The standard describes the structure. What an invoice must say for VAT purposes comes from the VAT Directive, Article 226, which opens:

The two conditions are separate, and from 1 July 2030 the VAT Directive says so in as many words: Member States must ensure that electronic invoices “(a) include the information required by this Directive; and (b) comply with the required technical standards on electronic invoicing” (new Article 218(4), inserted by Directive (EU) 2025/516). A file can pass every rule of the standard and still be a defective invoice, and the reverse.

Public buyers: since 2019

The deadline for central public buyers is set by the implementing decision: “18 April 2019 is the final date for bringing into force of the measures referred to in the first subparagraph of Article 11(2) of Directive 2014/55/EU” (Article 2). Member States could postpone it for sub-central buyers until 30 months after the reference was published (Directive 2014/55/EU, Article 11(2)).

Businesses: the default from 1 July 2030

ViDA makes the standard the default for invoices between businesses across the EU, with room for national standards for domestic supplies:

Of the five countries this site covers, France and Germany already base the formats they accept on it, as their guides set out; Italy and Poland require FatturaPA and FA(3). The table of national mandates shows which format each country requires today.

What the standard does not decide

• How the invoice travels. E-mail, a platform, a national clearance system or a network such as Peppol: the standard is silent on the channel.
• Whether it is mandatory. That comes from each country's law, and from 2030 from the VAT Directive.

CEN has published a new edition of part 1. Its catalogue lists EN 16931-1:2026 as published, ratified on 13 March 2026 and made available on 18 March 2026, superseding the 2017 edition and its amendment, which it lists as withdrawn. Its entry for the Official Journal reads “Citation expected for Directive 2014/55/EU”: the Official Journal still cites the 2017 edition through Implementing Decision (EU) 2017/1870.

The Commission states that the 2017 edition stays usable in the meantime: “The 2017 version will, however, remain compliant during the migration period.” The same Commission page dates the new edition to May 2026, where CEN gives March; this page reports both rather than choose.

The Commission also announces a change of instrument for public procurement: “replacing the current Directive with a Regulation that makes the European standard mandatory for public procurement (Q4 2026)”. That is a plan, not yet a text.

Reading the standard

Parts 1 and 2 of the 2017 edition can be obtained free of charge: “On 18 December 2018, the European Commission and CEN signed a License Agreement allowing cost-free access to the parts 1 and 2 of the eInvoicing standard”. The Commission marks that page as under review, and does not say whether the arrangement covers the 2026 edition. The other parts are sold by the national standards bodies.