In Belgium

The annual tax return (declaration fiscale) is the mechanism by which Belgian residents declare their income to the FPS Finance. For property owners, it is the primary interface for declaring property income and mortgage interest deductions.

What to declare. Section III of the tax return covers property income:

  • The cadastral income of all properties except the primary residence
  • For properties let for professional use: the actual rent received
  • Mortgage interest and capital repayments eligible for deduction

Filing methods.

  • Tax-on-web: online filing via MyMinfin (most common, deadline typically early October)
  • Paper return: mailed to the taxpayer, deadline typically end of June
  • Via accountant: accountant files on the owner’s behalf, extended deadline

How it works

Primary residence. Since the 2005 reform, the CI of the owner’s primary residence is not declared — it is exempt from personal income tax.

Additional properties. The CI of every other property owned must be declared: rental properties, second homes, unlet properties, properties abroad. The taxable amount is the indexed CI + 40%.

Professional letting. When letting to a company or for professional use, the owner declares the higher of: actual rent received, or indexed CI + 40%.

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Good to know
Since 2021, Belgian residents must also declare properties owned abroad. The FPS Finance assigns a Belgian-equivalent cadastral income to foreign properties, which must then be declared like any other additional property.

Practical example

Emma owns her primary residence (CI 1,100 EUR — not declared), a rental apartment (CI 900 EUR — declared), and a holiday home in France (CI equivalent assigned by FPS Finance: 1,500 EUR — declared). She files via Tax-on-web, entering both CIs in section III. Total declared property income: (900 + 1,500) x 2.1763 x 1.4 = 7,312 EUR, taxed at her marginal rate.

Key considerations

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Warning
Failing to declare a property’s cadastral income — whether in Belgium or abroad — constitutes tax fraud. The FPS Finance systematically cross-references land registry data, notarial deeds and international tax information exchanges to detect omissions.