Learn › Filing taxes (Belgium)

In short: For 2025 income you file in 2026 via Tax-on-web (MyMinfin) using eID or itsme, or on paper. The deadlines are 30 June 2026 (paper), 15 July 2026 (online) and 16 October 2026 (specific income). If you receive a correct proposed simplified return, you do not need to do anything (as of 2026; when in doubt, check the official source).

Filing your taxes in Belgium

Kontoo editorial team · Updated 06/24/2026

In Belgium, personal income tax is a federal matter run by the FPS Finance, but the country is federal: some taxes (registration duties, inheritance tax) belong to the Regions (Flanders, Wallonia, Brussels). For your 2025 income, you file in 2026 — online via Tax-on-web (MyMinfin) or on paper. Many taxpayers receive a pre-filled proposed simplified return. This chapter explains the process neutrally, for educational purposes; it is not individual tax advice.

  • Log in to MyMinfin (Tax-on-web) with your eID and a card reader, or via the itsme app. The platform opened on 28 April 2026 for declaring 2025 income.
  • Check whether you received a proposed simplified return: if the pre-filled data is complete and correct, you do not need to do anything; if not, you must correct it on time.
  • If you complete a full return, review every section (income, expenses, tax reductions) and add any missing data before you confirm.
  • Meet the deadline for your channel: paper 30 June 2026, online via MyMinfin 15 July 2026, and 16 October 2026 for specific income (self-employed, foreign professional income, etc.).

What matters

The personal income tax return covers the previous year’s income: in 2026 you declare your 2025 income (assessment year 2026). Personal income tax is a federal competence, managed by the FPS Finance, but Belgium is a federal state: the Regions (Flanders, Wallonia, Brussels) apply regional surcharges and manage other taxes such as registration duties and inheritance tax, which differ from one Region to another. The preferred way to file is Tax-on-web, reached via the MyMinfin portal, which opened on 28 April 2026; you log in with your eID and a card reader or via the itsme app. A paper return is still possible. Many taxpayers — typically those receiving a salary, pension or benefits without specific income — receive a proposed simplified return, pre-filled by the administration. If the data is correct and complete, no action is required; if not, you must correct it. Note: even with a simplified proposal, a return may still be mandatory in certain cases, for example if you hold foreign bank accounts.

ExampleIf your employer withheld too much wage withholding tax over the year, you may receive a refund after the tax is calculated; if too little was withheld, a balance will be due. Simplified example: a calculated tax of 8,000 € against 8,600 € already paid gives a 600 € refund. Conversely, 8,000 € owed against 7,400 € paid gives 600 € to pay. Actual amounts depend on your situation and the regional surcharges.
Record your deadlines and the expected amount in Kontoo to anticipate a balance due or a refund, and use the official MyMinfin (Tax-on-web) portal of the FPS Finance for the return itself.

In depth

Federal and regional

Personal income tax is federal, but the Regions apply regional surcharges that affect the final amount and manage their own taxes (registration, inheritance). The same situation can therefore lead to different amounts depending on whether you live in Flanders, Wallonia or Brussels.

Simplified proposal: checking still pays off

The proposed simplified return is convenient but remains a proposal. Comparing the pre-filled data with your supporting documents (income, deductible expenses, reductions you are entitled to) avoids paying more than necessary or missing an obligation. When in doubt, the MyMinfin portal and the FPS Finance are the reference sources.

Checklist

  • I know that in 2026 I declare the income I received in 2025.
  • I know the three deadlines: 30 June (paper), 15 July (online), 16 October (specific income).
  • I know that a correct proposed simplified return requires no action.
  • I know how to log in to MyMinfin via eID or itsme.

Common myths

Myth: If I receive a simplified proposal, I must always confirm it.

Reality: False. If the data is complete and correct, you do not need to confirm or return anything; you only act to correct errors or omissions.

Myth: All filing deadlines are the same for everyone.

Reality: False. The deadline depends on the channel and the type of income: paper 30 June, online 15 July, and 16 October for specific income (self-employed, foreign income, etc.).

Frequently asked questions

What should I do if I get a proposed simplified return?

Check the pre-filled data. If it is complete and correct, you do not need to confirm or send anything. If it is incorrect or incomplete, correct it via MyMinfin (before 15 July 2026) or with the paper reply form (before 30 June 2026).

What deadline applies if I have self-employed income?

For specific income such as self-employed or foreign professional income, the online deadline via MyMinfin is 16 October 2026 (as of 2026; check the official source when in doubt).

How do I log in to Tax-on-web?

Via MyMinfin with your electronic ID card (eID) and a card reader, or with the itsme app. The platform opened on 28 April 2026 for assessment year 2026.

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All lessons · Glossary · Editorial · Kontoo does the math and explains – this is general education, not tax, legal or financial advice.

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