đź“„ANNUAL RENT INDEXATION – Why it is NORMAL and LEGALLY REQUIRED
What is rent indexation?
The annual indexation is an adjustment of the rent based on the health index. This legal mechanism exists to ensure that the rent keeps pace with the rising costs in our society. It aligns the rent with the general increase in living expenses and costs.
The principle is simple: when the cost of living rises, the landlord’s expenses rise as well, and therefore the rent is adjusted proportionally.
It is a standard and normal practice that appears in almost every rental contract in Belgium.
This means that landlords have the right to apply indexation; it is not a matter of preference or a personal decision but a fixed part of rental law.
When is rent indexation applied?
In Belgium, annual rent indexation is fully provided for by law for the vast majority of rental contracts. It can be carried out every 12 months starting from the date the contract took effect.
Indexation with retroactive effect of up to 3 months
An important point many tenants do not know: the landlord may apply a missed indexation retroactively for up to 3 months.
This means:
- The current month can be indexed.
- The three preceding months may also be charged if the indexation was not applied on time.
This is fully permitted by law, provided the landlord does not go back further than three months.
Why does indexation happen?
Indexation is a general adjustment of all prices based on the health index, resulting in costs rising also for the landlord.
- Increasing costs for the landlord
Insurance, maintenance, repairs, materials, taxes, services and adminstrative costs and the general costs also become more expensive. - A fair and predictable market
Without indexation, the rent would become “less valuable” each year, while the landlord’s expenses continue to rise. Indexation provides stability and balance.
Indexation ensures that the rent remains proportionate to these rising costs for all parties.
How can you calculate the indexation yourself as a tenant?
As a tenant, you can also verify the calculation using the official Statbel indexation calculator or the formula in your contract. You need:
- the original rent amount,
- the base index of the month in which the contract started,
- the new index of the month in which the indexation is applied.
This shows exactly what amount may legally be requested.
Why do some landlords not always apply indexation?
When a landlord does not apply indexation, it is not because it is unnecessary or not allowed, but because it is a deliberate act of goodwill.
If your landlord chooses not to pass on rising costs—or not fully—to the tenant, this is their free choice and often depends on several factors, such as a smooth and problem-free tenancy, contract extensions, good upkeep of the property, good personal relations, etc…
Not applying indexation = a real DISCOUNT for the tenant
It is important for tenants to understand that when a landlord decides not to apply the annual indexation, this effectively means the tenant is receiving a genuine financial discount on the following year’s rent. By choosing not to pass on the legally permitted increase, the landlord voluntarily absorbs higher costs themselves. This is a significant act of goodwill and results in the tenant paying less than the legally indexed market value for the property.
Automatic indexation with real estate agencies
When renting through a real estate agency, indexation is usually applied automatically. These agencies work with professional software systems that:
- track every rental agreement,
- automatically indicate when indexation is allowed,
- and systematically perform the calculation.
There is no personal judgment or goodwill involved: the system simply applies what is legally provided.
Many landlords work with a real estate agency because this often removes worries, stress, and discussions regarding, for example, indexation, maintenance responsibilities, termination, etc. In return, the cost of the agency is often included in the rent.
Conclusion: rent indexation is not a punishment, but normal and legal
The annual rent indexation — including the possibility to apply it retroactively for up to three months — is a standard, legally embedded practice, even if it is not explicitly mentioned in the rental contract.
It serves to maintain balance and fairness in the rental relationship and is applied everywhere, especially in professionally managed rental properties.
It is therefore not a punishment or personal decision, but the normal and correct procedure.
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