Updated 25 September 2026. Belgium moved every domestic B2B invoice between VAT-registered businesses onto Peppol on 1 January 2026, in a single step with no size-based phasing. Nine months in, the structured flow works for Belgian-to-Belgian trade, while foreign supplier invoices, expense receipts and pre-2026 documents still arrive unstructured. That gap is where accounting firms still lose time.
Is e-invoicing mandatory in Belgium in 2026?
Yes. Since 1 January 2026, a Belgian-established, VAT-registered supplier must issue a structured electronic invoice to any VAT-registered customer for supplies located in Belgium, and the customer must be able to receive it. The obligation comes from the federal law of 6 February 2024 amending the VAT Code, as the European Commission's country page records.
When did the B2B mandate start, and is there any phasing?
It started on 1 January 2026 for everyone at once. Belgium chose a "big bang" rather than the turnover-based stages used in Germany or Poland, so there is no later deadline for small businesses. EY's tax alert notes the only carve-outs: non-established foreign suppliers and supplies where the customer's VAT number is not required.
Which format and platform does Belgium use?
Peppol BIS Billing 3.0 over the Peppol network, with Mercurius as the public sector's mailroom. Both parties may agree a different format provided it complies with EN 16931-1 and CEN/TS 16931-2. Belgium became the first country to pass one million registered Peppol invoice recipients, reported by VATupdate on 30 January 2026.
Does the mandate cover invoices from foreign suppliers?
No. A supplier not established in Belgium is outside the obligation, so invoices from Dutch, German, French or non-EU vendors keep arriving as PDF or paper, alongside employee receipts and older documents. That is the flow Invoreg is built for. Belgium also plans a near-real-time e-reporting layer in 2028, which will need line-level data for those inbound documents too.
Which VAT rates apply in Belgium and how does Invoreg map them?
21 % standard, 12 % and 6 % reduced, plus 0 % and exempt supplies. Invoreg reads the rate on every line, including mixed-rate hospitality and construction invoices, and maps each to the matching tax code in your accounting software. Belgium's VAT compliance gap was 12.3 % in 2023, above the EU average of 9.5 %, one reason the e-reporting layer is scheduled for 2028.
What should an accounting firm in Belgium do now?
Treat the Peppol flow as done and fix the remainder. Route foreign supplier invoices and receipts through email intake so they are read at line level, and use duplicate detection to catch the same invoice arriving once by Peppol and once by email. With one million recipients registered by January 2026, that double delivery is now a common error.
What Invoreg handles in Belgium today
- Belgian VAT numbers (BE + 10 digits, starting 0 or 1) on vendor records
- 21 %, 12 %, 6 % and 0 % VAT per line, plus exempt and reverse-charge lines, mapped to the tax codes in your accounting software
- Invoices in Dutch, French and German, including bilingual layouts common in Brussels
- Peppol BIS 3.0 XML received by your clients, read alongside the PDF copy so both are reconciled
- Duplicate flags across channels, so a bill delivered by Peppol and again by email is posted once
Related
Sources
- E-invoicing mandate deadlines — Invoice Navigator, accessed September 2026
- Belgium's mandatory e-invoicing to apply from 1 January 2026 — EY, accessed September 2026
- eInvoicing in Belgium — European Commission Digital Building Blocks, accessed September 2026
- Belgium becomes the first country to reach one million registered Peppol e-invoice recipients — VATupdate, 30 January 2026
- The EU's Questionable VAT Policy — Tax Foundation, 2 February 2026