Mistake 1 — Non-sequential invoice numbering
Belgian law requires unique and sequential numbering for each invoice. No gaps, no duplicates, no restarting mid-year. Incorrect numbering is a tax offence that can lead to fines during an audit.
Solution: use invoicing software that handles numbering automatically. Never use two different tools in parallel.
Mistake 2 — Missing mandatory legal notices
A Belgian invoice must include: your VAT number, the client's VAT number (B2B), the due date, the late payment interest rate, and the 40-euro flat-rate compensation. If you are under the VAT exemption scheme, the mention "VAT exemption scheme" is mandatory.
Solution: use a pre-compliant invoice template. Ledgerly adds all these mentions automatically based on your VAT regime.
Mistake 3 — Not requesting a deposit
Starting a project without a deposit puts you at risk of losing all your work if the client disappears. On projects over 1,000 euros, always request a deposit of 30 to 50%.
Solution: mention the deposit in your signed quote. Invoice it separately before starting. In case of dispute, the invoiced and paid deposit protects part of your fees.
Mistake 4 — Chasing too late (or not at all)
Statistics show: an unpaid invoice after 60 days has a 40% chance of never being paid. Yet many freelancers wait 45-60 days to follow up, out of embarrassment or forgetfulness.
Solution: set automatic reminders at +1, +15 and +30 days after the due date. Be systematic and professional — this is not harassment, it is rightful debt collection.
Mistake 5 — Not preparing for Peppol
From January 1, 2026, all B2B invoices between VAT-registered Belgian companies must go through the Peppol network. Freelancers still sending PDFs by email in 2026 will be non-compliant, with possible fines of 50 to 10,000 euros per non-compliant invoice.
Solution: migrate now to Peppol-compatible software. Migration is simple and free if you act before the deadline.