Rent indexation in 2026: what changes by region
The new rules for rent indexation in 2026 in Belgium. Calculation formula, EPC conditions, regional restrictions and implementation calendar for Brussels, Wallonia and Flanders.
What changes for rent indexation in 2026
The year 2026 marks a turning point for rent indexation in Belgium. Flanders joins Brussels and Wallonia in imposing EPC-related restrictions. For the first time, all three Belgian regions partially condition the right to indexation on the energy performance of the property.
The main changes:
- Flanders: properties rated F can now only index at 50%, G properties are blocked
- Brussels: restrictions maintained for E, F and G (unchanged since 2023)
- Wallonia: restrictions maintained for F (50%) and G (blocked) since 2025
Before requesting indexation in 2026, check the current EPC certificate for each property. An incorrectly applied indexation can lead to forced reimbursement and late-payment interest.
To automatically track indexation dates and EPC restrictions for each property, a rental management software has become essential.
The indexation calculation formula
The formula remains identical in all three regions:
Indexed rent = base rent x (new health index / starting health index)
The three elements of the formula
| Element | Definition |
|---|---|
| Base rent | The rent agreed at the signing of the lease (or the last revised rent) |
| New health index | The health index of the month preceding the lease anniversary |
| Starting health index | The health index of the month preceding the signing of the lease |
Calculation example
Lease signed on 1 March 2023 for a base rent of 850 EUR.
- Starting health index (February 2023): 127.92
- New health index (February 2026): 138.45
Indexed rent = 850 x (138.45 / 127.92) = 919.98 EUR, rounded to 920 EUR.
Health index vs consumer price index
Rent indexation uses the health index, which excludes alcohol, tobacco, petrol and diesel from its calculation. This index generally progresses more slowly than the consumer price index. The FPS Economy publishes the indices monthly on its website.
For a detailed explanation of the index mechanism, see our article on the health index and indexation.
Indexation rules by region in 2026
Brussels-Capital
- EPC A to D: full indexation authorised
- EPC E, F, G: indexation prohibited
- Effective date: in force since 14 October 2023
- Specificity: obligation to mention the EPC in the lease and in the listing
Wallonia
- EPC A to E: full indexation authorised
- EPC F: indexation limited to 50% of the formula result
- EPC G: indexation prohibited
- Effective date: in force since 1 January 2025
Flanders
- EPC A to E: full indexation authorised
- EPC F: indexation limited to 50% of the formula result
- EPC G: indexation prohibited
- Effective date: in force since 1 January 2026
Create a dashboard with the EPC of each property, the lease anniversary date and the corresponding indexation right. Update it each time a new EPC certificate is issued.
Comparative table
| EPC | Brussels | Wallonia | Flanders |
|---|---|---|---|
| A - D | 100% | 100% | 100% |
| E | Blocked | 100% | 100% |
| F | Blocked | 50% | 50% |
| G | Blocked | Blocked | Blocked |
To understand the detailed link between EPC and indexation, read our EPC guide and indexation ban.
How to index the rent in practice
Step 1: check the right to indexation
Check that:
- The lease includes an indexation clause (or does not explicitly exclude it)
- The property’s EPC certificate allows indexation in the relevant region
- The lease anniversary date has passed or is approaching
Step 2: calculate the new rent
Use the official formula with the indices published by the FPS Economy. Several online simulators are available (FPS Economy, BailBelgique).
Step 3: notify the tenant
Indexation is not automatic. The landlord must make the request in writing to the tenant. A simple letter, email or notification via the management platform is sufficient. The request can only have retroactive effect for the 3 months preceding the notification.
Step 4: apply the new rent
The new rent applies from the month following the notification (or from the anniversary month if the notification is made in time).
If the landlord does not index the rent within the year following the anniversary date, they permanently lose the right to indexation for that period. This right is time-barred and cannot be recovered retroactively.
Conclusion: plan ahead to avoid losses
Rent indexation remains a right of the landlord in Belgium, but a right that is now conditional. In 2026, all three regions impose EPC restrictions, and the trend is towards progressive tightening.
Key points to remember:
- The calculation formula remains unchanged (base rent x new index / old index)
- Flanders joins the system in 2026 for EPC F and G
- Indexation must be requested in writing, it is not automatic
- The limitation period is 1 year after the anniversary date
- Improving the EPC immediately restores the right to full indexation
To automate the calculation and tracking of your rent indexation, use our rental management platform. Generate compliant leases with a correctly configured indexation clause.
Frequently asked questions
-
The calculation formula remains the same: base rent x (new health index / starting health index). What changes in 2026 are the EPC-related conditions. In Flanders, properties rated F and G are now subject to indexation restrictions, which was not the case before.
-
Indexation is not automatic: the landlord must request it in writing from the tenant. If the tenant refuses to pay the supplement, the landlord can refer the matter to the justice of the peace. Note: the indexation claim is time-barred after 1 year. If the landlord does not index within the year following the anniversary date, they lose the right for that period.
-
Yes, short-term leases and student leases can be indexed if the lease provides for it and the effective duration exceeds 1 year. For a 10-month student lease, indexation has no practical time to apply. For a 2 or 3-year short-term lease, annual indexation applies normally.
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