What is the indexed cadastral income
The indexed cadastral income (revenu cadastral indexe) is the base cadastral income multiplied by an annual indexation coefficient (based on the consumer price index, not the health index). It is used for property tax calculation and tax declarations — it is distinct from rent indexation.
Key characteristics:
- Base cadastral income (RC): a notional annual rental value set by the administration (last general revision: 1975, adjusted for new builds)
- Indexation coefficient: set annually by royal decree, following the CPI
- Indexed RC: Base RC x Coefficient
- Uses: property tax base, tax declaration, some social assessments
How the indexed cadastral income is calculated
The calculation is straightforward:
Indexed CI = Base cadastral income x Annual indexation coefficient
For example, with a base CI of 1,500 EUR and a 2026 coefficient of 2.1763:
Indexed CI = 1,500 x 2.1763 = 3,264.45 EUR
This indexed CI serves as the base for property tax calculation (applying regional and municipal rates).
You can find your base cadastral income on your property tax notice (avertissement-extrait de role) or on MyMinfin (FPS Finance online portal). The annual indexation coefficient is published in the Moniteur belge (Belgian Official Gazette).
Cadastral income indexation vs rent indexation
These are entirely different mechanisms:
| Aspect | Cadastral income indexation | Rent indexation |
|---|---|---|
| Index used | Consumer price index | Health index |
| Applies to | Property tax base | Monthly rent |
| Who decides | Government (automatic) | Landlord (on request) |
| Frequency | Annual (automatic) | Annual (on request) |
| Impact on tenant | None (paid by landlord) | Direct (higher rent) |
The two are completely independent. A change in the indexed cadastral income has no effect on rent indexation, and vice versa.
Regional specifics
Brussels-Capital Region
The indexed CI serves as the base for Brussels property tax. Regional and municipal surcharges vary significantly across Brussels communes. The Ordinance of 27 July 2017 does not modify cadastral income rules.
Wallonia
In Wallonia, the indexed CI is the base for the precompte immobilier. Municipal surcharges can be substantial, making the effective tax rate quite high in some communes. The Decree of 15 March 2018 does not affect cadastral income.
Flanders
In Flanders, the indexed CI is used differently following the reform of property taxation. The Flemish Housing Rental Decree of 9 November 2018 does not affect cadastral income rules.
Income Tax Code 1992 (CIR 92), articles 13 and 518. The indexation coefficient is set annually by Royal Decree.