Rent is for the lessor an income similar to any other income. It is therefore logical to align rental income with other income, by providing him with the possibility of adapting it to the cost of living: this adaptation is called indexation.

You can check the latest indexation figures on:

https://statbel.fgov.be/fr/themes/prix-la-consommation/indice-sante

Indexation once a year

The rent can be indexed once a year, except when it is stipulated in the contract that no indexation takes place. The indexed amount is  based on the rental price indicated in the rental agreement. The owner must request this indexation in writing.

3 months retroactive effect

The indexation is applicable with a maximum retroactive effect of 3 months. For instance, the landlord is asking for indexation in December, he can claim the new indexed rent only from September on - 3 months earlier. What happens if the tenant doesn’t comply to this request? Then, the lessor has a maximum period of 1 year after his request to call for court and require that the lessee pays the amount of the indexation.

Easy calculation? Go to the following link

https://statbel.fgov.be/fr/themes/prix-la-consommation/indexation-du-loyer