Belgium’s Paper Tax Return Deadline Arrives, Online Filing Open Until July 15
Today, June 30, marks the final deadline for submitting paper tax returns in Belgium for income year 2025 (tax year 2026). Taxpayers who file online via Tax-on-web (MyMinfin) have until July 15 to complete their submissions, while those with complex returns—such as foreign or self-employment income—benefit from an extended deadline of October 16, according to VRT NWS.
A Declining Practice
The number of Belgians filing paper tax returns has dropped sharply in recent years. In 2021, approximately 315,000 paper returns were submitted; last year, that figure fell to just 141,000—representing only about 4% of all tax filings. Francis Adyns, spokesperson for the FOD Financiën (Federal Public Service Finance), described the practice as a “marginal phenomenon” in comments to VRT NWS.
Despite this digital shift, the government maintains the paper option to ensure accessibility. “As a government, we must still ensure that people who are not digitally literate can fulfill their tax obligations,” Adyns said.
Online Filing and Simplified Proposals
For the vast majority of taxpayers, digital filing via Tax-on-web on the MyMinfin portal is the standard method. Approximately 56% of Belgian taxpayers—around 3.9 million people—receive a pre-filled simplified tax return proposal (voorstel van vereenvoudigde aangifte). According to the FOD Financiën, 93% of recipients accept the proposal without changes.
However, the tax authorities strongly advise reviewing all pre-filled data carefully. Missing information—such as childcare costs, charitable donations, or dependent children—can lead to missed deductions or overpayment. “A quarter-hour of checking can ultimately yield more than you think,” noted Sarah Maes, journalist at Nieuws365.be.
Key Deadlines to Remember
The FOD Financiën outlines three critical dates for the 2026 tax filing season:
- June 30, 2026: Deadline for paper tax returns (must be received by the tax authorities)
- July 15, 2026: Deadline for online filing via Tax-on-web / MyMinfin
- October 16, 2026: Extended deadline for complex returns involving foreign income, self-employment income, or other specific categories
Taxpayers who file online can correct their return once until July 15. After that date, corrections require direct contact with the FOD Financiën.
Common Mistakes to Avoid
Consumer organization Test-Aankoop highlights several frequent errors that can cost taxpayers money:
- Incorrectly claimed dependent children (kinderen ten laste)
- Missed deductions for childcare, including summer camps
- Unreported alimony payments or receipts
- Forgotten charitable donations and gifts
- Undeclared foreign bank accounts and life insurance policies
- Dividend withholding tax (roerende voorheffing) not properly claimed
- Commuting expenses (woon-werkverkeer) not correctly reported
- Changes in family situation (marriage, divorce, birth) not updated
Implications of Missing Deadlines
Late submissions can result in fines or stricter tax audits. The FOD Financiën emphasizes that even taxpayers who receive a simplified proposal should not assume it is automatically correct—information may be missing if organizations failed to submit data or if a national registry number was absent from a certificate.
Digital Transformation and Accessibility
The steady decline in paper returns—a 55% drop over four years—reflects Belgium’s successful digitalization of tax administration. The Tax-on-web platform has become the primary channel for the vast majority of filers. However, the government’s commitment to maintaining paper options acknowledges the persistent digital divide, ensuring that elderly citizens and those without internet access can still comply with their obligations.
As the tax season progresses, taxpayers are encouraged to review their returns carefully, whether filing on paper today or online in the weeks ahead. The assessment notices (aanslagbiljet) will be sent between August 2026 and June 2027, providing the final calculation of taxes owed or refunds due.
What to Watch For
With digital adoption accelerating, questions remain about whether the FOD Financiën will eventually phase out paper returns entirely. For now, the hybrid system balances efficiency with accessibility—but the trend line is clear. Taxpayers who have not yet filed are urged to act promptly to avoid penalties and ensure they claim all deductions to which they are entitled.