Cadastral income and property tax
What is cadastral income? Calculation, indexation, revision and impact on property tax.
What is cadastral income
The cadastral income (revenu cadastral, RC) is a fictitious net income that a property would have generated in 1975. It is the cornerstone of Belgian property taxation: property tax, income tax on rental income and registration duties all use it as a base.
Every property in Belgium has a cadastral income set by the Cadastre Administration (Administration Generale de la Documentation Patrimoniale). The CI has never been globally revised since 1975. Individual revisions occur after construction, renovation or change of use.
For landlords, the CI is critical because Belgian rental income is taxed on the indexed CI (not on actual rent), which is considerably more favourable than taxation on actual income.
Indexed cadastral income
The indexed CI is the CI multiplied by the annual indexation coefficient set by royal decree. For 2026, the coefficient is 2.1016.
Example: a property with a CI of EUR 1,200. Indexed CI = 1,200 x 2.1016 = EUR 2,522. This indexed CI serves as the base for property tax calculation and rental income taxation.
The indexed CI increases every year with inflation, even though the base CI remains fixed.
Impact on landlord taxation
Property tax
Property tax = indexed CI x 1.25 % x (1 + surcharges). The CI directly determines the annual property tax amount.
Income tax
When the property is let to a natural person for residential use, the landlord is taxed on the indexed CI increased by 40 %, not on the actual rent received. This is a major advantage: actual rent is typically 3 to 5 times higher than the taxable base.
| Element | Amount |
|---|---|
| Actual annual rent | EUR 10,800 |
| Indexed CI + 40 % | EUR 3,531 |
| Taxable base | EUR 3,531 (vs EUR 10,800 actual) |
Mortgage interest is deductible from this real estate income, further reducing the tax burden.
Revision and disputes
The CI can be revised by the Cadastre Administration after:
- New construction
- Major renovation (with planning permit)
- Change of use (residential to commercial)
- Division or merger of units
If you disagree with a CI revision, you have 2 months to object from the notification date. An expert valuation can support your objection.
A lower CI means lower property tax and lower income tax. Monitor CI revisions carefully, especially after renovation works. Store all CI documentation in your rental management software.