Rent indexation calculator, Belgium

Base rent (as written in the lease)

€

Region

PEB / EPC certificate class

Lease signature date

The lease took effect on a different date than the signature

Lease effective date

The lease is registered with the Federal Public Service Finance The lease is also registered with Bruxelles Logement (mandatory since 1 January 2025) The PEB/EPC certificate was handed to the tenant

Health-index figures come straight from Statbel and are refreshed automatically, nothing here is a fixed table that can go stale.

Indexed rent —

vs. today—

Starting index—

Current index—

Increase—

Get the letter to send your tenant

A ready-to-send template for your region, with the full calculation detail.

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Once a year, on the anniversary

Indexation may be applied once per year, on the anniversary of the lease taking effect.

Only three months are recoverable

The request is not retroactive beyond three months, every month before that is permanently lost.

The energy rating can cancel it

In all three regions, a lease from before autumn 2022 with a poor energy rating keeps a correction factor from the 2022-2023 freeze: Brussels (PEB E-G, before 14/10/2022), Flanders (EPC D-F, before 01/10/2022), Wallonia (PEB D-G, before 01/11/2022), computed automatically above.

Questions, answered

Where do these figures come from?

The health index is Statbel’s official series, refreshed automatically inside Proporio. The Brussels PEB correction factor is re-entered from the official be.brussels table whenever it is republished. The Flemish and Walloon factors are computed from the health index of the 2022-2023 freeze year, as their decrees define them (Flemish decree of 3 October 2022, art. 4; Walloon decree of 19 October 2022).

What about Flanders and Wallonia?

Both froze or capped the indexation of energy-poor dwellings for one lease year (Flanders 01/10/2022, 30/09/2023: EPC D at 50 %, E/F at 0 %; Wallonia 01/11/2022, 31/10/2023: PEB D at 75 %, E at 50 %, F/G at 0 %) and forbid catching up afterwards. For a lease in force before those dates, the tool applies the resulting correction factor to every later indexation. New leases, and labels A to C, are indexed in full.

Must I notify the tenant?

Yes. Indexation is not automatic on the tenant’s side: you have to ask for it in writing, and it only takes effect from that request, that is exactly the letter this tool emails you.

Everything connects in Proporio

Brussels, Flanders, Wallonia →

Deposit, notice, registration and indexation, side by side.

What a lease must contain →

Mandatory clauses, forbidden ones, and the deadlines that bite.

Built for Belgium →

Health-index indexation, leases for all three regions, in French and Dutch.

The index for every anniversary month

One page per month and region: the health index to use, a worked example, and the regional certificate rule.

Belgium 2026 Brussels 2026 Flanders 2026 Wallonia 2026 Belgium 2024 Belgium 2025

Never miss an indexation again

Proporio watches every anniversary, computes the new rent and drafts the letter. You approve.

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Index a rent, correctly