This week is the last for some people paying taxes in Belgium to submit their tax returns. The deadline to file the paper version is Monday 30 June.
While only a minority of Belgian taxpayers opt to file their taxes on paper, the Finance Ministry still received around 200,000 physical forms by post last year. Here is how to make sure that your paper tax return correctly reaches the correct authorities:
- the document must be sent to the correct address indicated on the documents in the 'brown envelope' that holds the necessary documents (it should not be deposited in an office),
- the declaration or form received in the mail must be used (this means: not a copy, not someone else's document and not a previous year's document),
- the envelope must be sufficiently and properly stamped.
As the paper tax return (as well as any changes to the simplified return proposal via the paper response form) must be submitted by 30 June 2025, people using this method are advised to still send the post this week: sending it on 30 June itself risks being too late.
However, the authorities warn that the chance of making mistakes when submitting a paper return is "much greater" than with an online tax return. "Only 33% of paper tax returns can be processed automatically, compared to 79% for online tax returns."
The switch to online tax returns can be made at any time, either by yourself, by authorising a citizen (family member or friend) or by an accountant, until 15 July 2025 or, if you have specific income, until 16 October 2025.
Those who need help completing their tax return can easily obtain it via the website or contact page of the Finance Ministry, the website mapremieredeclaration.be (especially for citizens who have to complete a tax return for the first time), or the telephone number 02/572 57 57 every working day from 09:00 to 17:00.
What happens if you file late?
As the tax authorities consider filing late the same as not filing at all, this can have serious consequences.
- People filing late could face an administrative fine ranging from €50 to €1,250. That amount increases depending on how many times you filed late before.
- The tax authorities may decide to impose a tax increase of 10% to 200%, either instead of or on top of the fine. (If the undeclared income is less than €2,500, this increase will be waived.)
- The Finance Ministry will take more time to check a late tax return, with the investigation period as much as 1.5 years longer.
- The burden of proof is reversed. Normally, if the Finance Ministry wants to refute something that is in a timely return, they have to provide the evidence for it. But if the citizen is late, this is turned around: they have to provide the proof themselves. This is especially true for the self-employed.
What if you make a mistake?
From now on, the Finance Ministry will overlook the first mistake made when submitting tax returns, as they announced at the start of tax season (28 April). While mistakes can theoretically result in fines, this new policy exempts first-time errors.
Under the updated approach, initial errors will be corrected without penalties. In practice, this leniency has been applied in recent years but it is has now been made official policy, the Finance Ministry noted.
