Rent indexation in Belgium: overview
Rent indexation in Belgium follows a common national principle — the health index — but is applied differently across the three regions. Rent indexation is based on a written lease and a health index published monthly by Statbel.
The principle is identical everywhere: base rent set at the signing of the lease, annual adjustment on the anniversary of the entry into force, increase capped by the consumer price index (health index) and consumer prices recorded by Statbel.
What differs is the regional framework:
- Walloon Region: decree of 15 March 2018, indexation blocked from EPC F since 1 November 2022.
- Brussels-Capital Region: Brussels Housing Code, ordinance of 14 October 2023 and correction factor.
- Flemish Region: Flemish decree, own rules.
For the general framework: indexation pillar guide. By region: Wallonia — Brussels.
Rent indexation Belgium: 3-region comparison table
The table summarises the key differences in 2026:
| Criterion | Wallonia | Brussels | Flanders |
|---|---|---|---|
| Legal text | Walloon Decree 15 March 2018 | Brussels Housing Code | Vlaams Woninghuurdecreet |
| EPC A-D | 100% indexation | 100% indexation | 100% indexation |
| EPC E | ~50-75% indexation | Progressive correction factor | Variable |
| EPC F | 0% (blocked) | Reduced factor | Flemish rules |
| EPC G | 0% (blocked) | Very reduced or nil factor | Flemish rules |
| No EPC | 0% (treated as G) | Treated as EPC G | Per Flemish rules |
| Key date | 1 November 2022 | 14 October 2022 and 2023 | Flanders-specific |
All three regions use the same monthly health index but apply their own correction factor. This system aims to encourage energy renovation while controlling rent increases.
Indexation history by year: 2022 — 2026
Since 2022, rent indexation in Belgium has been marked by the energy crisis. Here is an overview by year:
Rent indexation Belgium 2022
Before the energy shock, indexation followed standard rules. Restrictive measures came into force at the end of the year: 1 November 2022 in Wallonia, 14 October 2022 in Brussels.
Rent indexation Belgium 2023
In 2023, the EPC block was fully applied. Many landlords with EPC F/G ratings could not index. In Wallonia, the freeze period ended on 31 October 2023. In Brussels, the ordinance of 14 October 2023 adjusted the mechanism.
Rent indexation Belgium 2024
In 2024, each region stabilised its mechanism. The health index saw smaller fluctuations than in 2022-2023.
Rent indexation Belgium 2025
The 2025 figures show stabilisation. Energy-inefficient properties remain penalised in all three regions.
2026 and beyond
In 2026, the principle remains the same. Rules have been renewed, sometimes with minor adjustments. Watch for any new regional reform.
Rent indexation formula Belgium: the common principle
The national rent indexation formula:
Indexed rent = Base rent x (New index / Starting index) x Regional EPC factor
- Base rent: amount at the entry into force of the contract.
- Starting index: health index for the month preceding the signing.
- New index: health index for the month preceding the anniversary of entry into force.
- EPC factor: 0 to 1 depending on the class and the region.
The mathematical calculation is the same everywhere. Only the EPC factor differs. For detailed steps: calculation guide. Also consult the health index table.
Calculate rent indexation Belgium: all systems
To correctly calculate rent indexation in Belgium, you need:
- The region where the property is located (Wallonia, Brussels or Flanders).
- The EPC class of the property.
- The date of entry into force of the lease.
- The two health indices to compare.
Our free indexation calculator automatically applies the rules of the chosen region. It indicates whether you can index the rent and at what rate.
Indexation letter Belgium: national rules
The indexation letter must include mandatory information in all three regions: identification of the parties, reference to the lease, base rent and new amount, the two indices used, and the effective date.
Registered post is strongly recommended. Letter template — Online registered letter.
For regional details: Wallonia — Brussels — EPC and indexation — Tenant verification.