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Rent indexation calculator (Belgium)

Free, independent tool based on the Statbel health index and compliant with the Law of 6 August 1993. Covers ordinary residential leases in Wallonia, Brussels and Flanders — with automatic handling of the regional EPC rules.

Single step

A few details.
The calculation from your data.

Property region, lease dates, initial rent, EPC class. The calculation runs instantly.

Property region
€ / month
€
coefficient 100%
Result · real-time
New indexed rent
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LEGAL FORMULA APPLIED
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How the calculation works

Rent indexation in Belgium follows a single formula governed by the Law of 6 August 1993 and the Royal Decree of 24 December 1993. It uses the raw health index published monthly by Statbel, which excludes volatile products (alcohol, tobacco, fuel).

Indexed rent = Base rent × (New index ÷ Starting index)

The new index is always that of the month preceding the anniversary of the lease's entry into force. The starting index depends on the region: the month preceding the signature of the lease in Brussels and Wallonia; the month preceding its entry into force in Flanders for leases concluded since 1 January 2019. That is why the form asks for both dates. Anniversaries, the Walloon 2022-2023 period and the regional cut-off dates are always determined by the entry into force.

Why our calculator displays an EPC factor

Since 2022, all three regions take the energy performance of the property into account. In Brussels and Flanders, a correction factor multiplies the full result of the ordinary formula; Wallonia applies a special method:

  • Brussels (Brussels Housing Code, art. 224/2 § 1/2): for leases that entered into force before 14 October 2022, a correction factor set by anniversary month — roughly 0.945 to 0.990 for EPC E, 0.891 to 0.980 for EPC F or G. EPC A to D and more recent leases: 100%.
  • Flanders (decree of 3 October 2022): for contracts that entered into force before 1 October 2022, a factor of roughly 0.945 to 0.980 for EPC D and 0.891 to 0.960 for EPC E, F or no EPC. EPC A+ to C and more recent contracts: 100%. Label G does not exist in Flanders.
  • Wallonia (decree of 19 October 2022): no factor, but a special method for leases with EPC D to G or no certificate that had an anniversary between 1 November 2022 and 31 October 2023 — the calculation starts from the rent as adapted during that period. Other leases follow the ordinary formula at 100%.

The calculator automatically applies the rule that matches the data you enter and shows the calculation in two steps (ordinary formula, then regional factor or method). See the limits of the tool for the cases it does not cover.

Documents to prepare

  • The lease contract (signature date and entry-into-force date)
  • The amount of the initial rent (excluding charges)
  • The property's energy class (EPC, depending on the region)
  • The year for which you are requesting indexation

Dedicated regional calculators

For a calculation pre-filled with the regional legal context, use:

Frequently asked questions

How is rent indexation calculated in Belgium?
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The legal formula is: Indexed rent = Base rent × (New index ÷ Starting index). The new index is the health index of the month preceding the anniversary of the lease's entry into force. The starting index is that of the month preceding the signature of the lease in Brussels and Wallonia, and that of the month preceding its entry into force in Flanders for leases concluded since 1 January 2019. In Brussels and Flanders, the result is then multiplied by an EPC correction factor for certain leases that entered into force before 14 October 2022 (Brussels) or 1 October 2022 (Flanders).

On which date does indexation take effect?
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On the anniversary date of the lease's entry into force (not the signature date). If your lease entered into force on 1 July 2021, indexation takes effect on each subsequent 1 July.

Which health index should be used?
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The raw health index published by Statbel (not the smoothed health index, which is used for salaries). The calculator automatically selects the correct base year (1988, 1996, 2004, 2013 or 2025) according to the date the lease was signed.

Does the lease need to be registered to apply indexation?
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In Brussels and Wallonia, yes: the lease must be in writing and registered. In Brussels, the EPC (PEB) certificate must also have been provided to the tenant, otherwise no indexation is due. In Flanders, the lease must be in writing and no EPC is required to index. In the three Regions, indexation is never automatic: it has to be requested in writing.

Can I claim several years of forgotten indexation?
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No. A late request only reaches back over the 3 months preceding the month of the request, in all three regions. Beyond that, the indexation is permanently lost for the unclaimed period.

Is the calculator's result legally binding?
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The calculator strictly applies the legal formula with the official Statbel indices. It serves as a reliable reference, but in case of dispute the justice of the peace makes the final ruling (low-cost procedure, no lawyer required). Our PDF notification letter is designed to provide all the expected supporting documentation.

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