Invoicing Clients in Belgium: Legal Requirements for Freelancers
One of the most paralyzing moments for a new freelancer in Belgium is staring at a blank screen, wondering if a missing VAT number will trigger a massive audit. I still remember the cold sweat I broke into when my first big client rejected my invoice because I forgot to include my CBE number. This guide solves the complex puzzle of Belgian invoicing by breaking down every legal requirement and 2026 digital update.
The Anatomy of a Legally Compliant Belgian Invoice
If you have already navigated Setting Up as an Independent (Indépendant) in Belgium, you know that the Belgian state loves its paperwork. An invoice is not just a request for payment; it is a legal document that must follow a specific "recipe." If one ingredient is missing, the invoice is technically invalid, which means your client cannot legally deduct the VAT, and you might face issues during your quarterly declarations.
Every invoice you issue must contain a set of mandatory mentions. First and foremost, you need your full business name and registered address. If you are a natural person (eenmanszaak/entreprise individuelle), this is your name. If you have a company (BV/SRL), it must be the official name in the statutes. You must also include your "enterprise number" (CBE/KBO). This is the ten-digit number starting with 0 or 1 that defines your business identity. Ensure it is preceded by "VAT BE" or "TVA BE" if you are registered for VAT.
The invoice date and a unique, sequential invoice number are non-negotiable. I always recommend a format like 2026-001 so you can easily track your records year by year. You must also clearly state your client’s information: their name, registered address, and their VAT number if they are a business. Finally, the description of goods or services must be detailed enough for an auditor to understand what happened. Writing "Consulting" is often too vague; "10 hours of UX Design consulting for June 2026" is much safer.
Understanding the VAT Maze and 2026 Rates
Navigating VAT is where most expats get tripped up. In Belgium, the standard VAT rate is 21%, but depending on your industry, you might deal with 12% or 6%. When you were Applying for a VAT Number (TVA/BTW) as a Freelancer, you likely chose a specific regime. On your invoice, you must break down the price: the net amount, the VAT rate applied, the total VAT amount, and the final "TTC" (all taxes included) price.
There are specific scenarios where you do not charge VAT. If your annual turnover is low, you might be under the Exemptions for Small Businesses (Franchise de la Taxe) under €25,000. In this case, you do not charge VAT, but you must include the specific legal mention on your invoice: "Bijzondere vrijstellingsregeling kleine ondernemingen" or "Régime particulier de franchise des petites entreprises." Without this text, the tax office assumes you simply forgot to charge tax.
Another common scenario for freelancers working with international clients is the "Reverse Charge" (autoliquidation). If you provide services to a business in another EU country, you usually do not charge Belgian VAT. Instead, the client pays VAT in their own country. For this to be legal, your invoice must clearly state: "VAT Reverse Charge – Article 196 of Directive 2006/112/EC." This shifting of responsibility is a lifesaver for cross-border work, but it requires you to verify the client's VAT number via the VIES system before sending the file.
| Feature | Requirement | Notes |
|---|---|---|
| Sequential Numbering | Mandatory | No gaps allowed in your numbering system. |
| Client VAT Number | Mandatory for B2B | Must be verified for EU-wide transactions. |
| VAT Breakdown | Mandatory | Show net, rate %, and total VAT separately. |
| Currency | Euro | Can show other currencies, but Euro is the base for tax. |
| Language | NL/FR/DE | Depends on your region, but English is often accepted B2B. |
| Peppol ID | Mandatory (2026) | Needed for the new digital B2B mandate. |
The 2026 B2B e-Invoicing Mandate
Welcome to the future of Belgian administration. As of January 1, 2026, Belgium has implemented a mandatory electronic invoicing (e-invoicing) system for all B2B transactions between Belgian-established companies. This is a massive shift away from the "PDF-by-email" culture we used to enjoy. If you are invoicing a Belgian business client, a standard Word doc or simple PDF is no longer legally sufficient.
The system relies on a network called Peppol. Instead of sending a file manually, your invoicing software sends a "structured" data file (usually in XML format) directly to your client’s accounting software. This allows the Belgian tax authorities to have real-time or near-real-time visibility into transactions to combat VAT fraud. To stay compliant, you must use a tool that supports Using E-invoicing Systems (Peppol) for B2B Clients in Belgium.
For freelancers, this means you need to subscribe to a compliant software platform. You can no longer just wing it with a handmade template. While this feels like another bureaucratic hurdle, the silver lining is that it automates much of your record-keeping. If you find the technical side daunting, taking a short course on platforms like Coursera or Udemy can help you understand the data structures behind these new systems. It is also a great time to brush up on professional terminology; using Lingoda to improve your French or Dutch business vocabulary will help you navigate the software interfaces which are often localized.
Language Requirements and Cultural Norms
In Belgium, the language of your invoice can actually be a legal sticking point. According to the language laws, if your business is registered in the Dutch-speaking region (Flanders), your official documents—including invoices—should technically be in Dutch. If you are in Wallonia, they should be in French. Brussels is bilingual, but the rule generally follows the language of the person you are communicating with.
In practice, most international B2B clients accept English. However, if you are working with a local Belgian company or a government entity, sticking to the regional language is not just a sign of respect—it can prevent legal disputes later. If you are struggling with the transition, using resources like FrenchPod101 or DutchPod101 can give you the specific phrases needed for invoicing, such as "Veuillez trouver ci-joint notre facture" or "Bijgaand vindt u onze factuur."
Furthermore, keep in mind the Belgian payment culture. The standard payment term is 30 days, although many freelancers negotiate for 15. If a client is late, the law allows you to charge interest and a flat recovery fee, but this must be stated in your "General Terms and Conditions" which should be linked or attached to every invoice. If you haven't set these up yet, consult our guide on Social Insurance Funds for Freelancers (Xerius, Acerta, Partena) as they often provide legal templates for new independents.
Record Keeping and Audit Protection
Issuing the invoice is only half the battle. Belgian law requires you to keep copies of all invoices (incoming and outgoing) for seven to ten years. In the digital age, this means keeping secure, timestamped backups. Since the 2026 e-invoicing mandate is in full swing, your digital "archive" must be able to prove the integrity and authenticity of the files.
If you ever decide to stop freelancing, perhaps because you found a great role through Job Hunting in Belgium: Strategy for Non-EU and English Speakers, you cannot just delete your files. You are still responsible for those records for years after the business closes. Many freelancers opt for Freelancing via a Payroll Company (Portage Salarial) in Belgium specifically to avoid this administrative headache, as the company handles the legal invoicing requirements on their behalf.
Finally, always cross-reference your Freelance Taxes: Social Security, Withholding, and VAT Deadlines. An invoice that isn't paid still counts toward your turnover if you are on an accrual-based accounting system. Understanding the difference between your Gross vs Net Salary in Belgium: Why the Difference is So Big will help you set aside enough from each paid invoice to cover your social security and income tax at the end of the year.
Disclaimer
This guide is for informational purposes only and does not constitute legal or financial advice. Belgian tax laws and e-invoicing regulations are subject to frequent change. Always consult with a certified Belgian accountant (comptable/boekhouder) to ensure your specific business setup is compliant with the latest SPF Finances requirements.
