EN 16931

What it means

EN 16931 is the European standard that defines the mandatory content and structure of an electronic invoice so that software in any EU country can process it automatically. It sets out a semantic model, a list of data elements such as supplier, customer, line items, VAT rates and totals.

The standard was created under the directive on electronic invoicing in public procurement. Public buyers in the EU must accept e-invoices that comply with it, so a supplier from one country can invoice an authority in another without a special format.

Concrete technical formats such as UBL or CII, the Peppol network and upcoming mandatory business-to-business e-invoicing are built on it. Slovakia is preparing mandatory e-invoicing between VAT payers, which is to be based on EN 16931.

How it works in practice

A PDF invoice is not an e-invoice under the standard, because software cannot read it reliably. An e-invoice is a structured file, usually XML, that the recipient's accounting system loads automatically without retyping, saving time and reducing errors.

Companies supplying the public sector should check that their invoicing software can create an EN 16931 invoice and send it through the required channel. Software vendors are gradually adding format support and Peppol connectivity.

An e-invoice must contain all the invoice particulars required by VAT law, and the standard adds structured codes, for example for units, rates and exemption reasons. Missing or wrong data can lead to the invoice being rejected by the recipient's system.

What to watch out for

The move to structured invoices should be planned early. Code lists, customer master data and approval processes need adjusting, and incoming invoices should be matched automatically to orders, or the benefits of automation are lost.

E-invoices must also be retained for the statutory periods in their original electronic form, preserving authenticity of origin and integrity of content. Printing and keeping only a paper copy may not be enough.