An “ordinary” electronic invoice contains all the mandatory data for an invoice and is issued and received in electronic form, whatever the form. This is therefore the broad definition of an electronic invoice, pursuant to the VAT legislation.

It concerns an electronic invoice which is drawn up, sent and received in a structured electronic form. This enables it to be processed automatically and electronically. Pursuant to the VAT legislation, this is the strictest definition of an electronic invoice. This type of invoice will be compulsory as from 1 January 2026 for transactions between two Belgian enterprises liable to VAT (B2B).

Structured electronic invoices must comply with the European semantic and syntax standards EN 16931-1 and CEN/TS 16931-2 (hereinafter jointly mentioned as EN16391 or the European standard).

In concrete terms, this means that invoices must be issued in Peppol-BIS format. This already applies also to transactions between companies and public authorities (B2G).

You can only depart from this if both parties agree and if the alternative format also complies with the same European standard.

Structured electronic invoices must always be able to be sent and received via the Peppol network.

You can only depart from this if both parties agree.

An alternative format may comply with the European standard if this format can be converted into an invoice that complies with the rules of the European standard. This means that the mandatory key elements of the invoice:

• are present in sufficient number (cardinality);
• have the same meaning (semantics);
• are calculated in the same way (syntax) (e.g. rounding up or down rules).

PDF invoices are still legal in all situations till 31 December 2025.

As from 1 January 2026, structured electronic invoicing will be compulsory for all transactions between Belgian enterprises liable to VAT.

For all other transactions, PDF invoices will also remain valid after 1 January 2026. This is the case, for example, for transactions with private customers (B2C) or international billing (within and outside the EU).

B2B invoicing in Belgium	Until 2025	As from 2026
Paper invoice	authorised	not authorised
Invoice Peppol-BIS via the Peppol network	authorised*	mandatory
E-invoice (convertible into EN16931)	authorised*	authorised**
Other formats (e.g. PDF, Excel, Word ...)	authorised*	not authorised

* For electronic invoicing before 1.1.2026, you need the recipient's agreement. Registration on the Peppol network is considered as agreement. This allows you to see for yourself which customers are ready and willing to receive structured electronic invoices.

** The use of an alternative format and transmission method is only possible by mutual agreement, and in compliance with European standard EN16931