Rent indexation in Brussels: formula and EPB rules

The conditions

Under art. 224/2 of the Brussels Housing Code, indexation is possible if:

1. the lease is written and does not exclude indexation;
2. the lease has been registered;
3. the landlord has given the tenant a valid EPB certificate. If the certificate has expired, a new one must be given before any indexation.

These registration and EPB requirements apply since 14 October 2022. Without them, the rent cannot be indexed.

The formula

indexed rent = base rent × new health index ÷ initial health index

• Base rent: the rent stated in the lease.
• Initial index: the health index of the month before the lease was signed.
• New index: the health index of the month before the lease anniversary.

The index tables are published by Statbel (the federal statistics office), and the Region offers a downloadable Excel calculator with the Brussels rules. Statbel also offers an online rent calculator. The Brussels Excel tool can be used for residential leases until 31 October 2026, and the regional calculation module is updated on the 5th of each month, according to be.brussels.

Example from the regional brochure: a lease signed in November 2017 and starting on 1 January 2018 at €700. The base rent is €700, the initial index is October 2017, and each year the new index is that of December.

The formula in one line

Indexed rent = base rent × new index ÷ initial index, using the health indices published by Statbel for the months named above. The result is a ceiling: the landlord may ask less, never more. The Region’s online calculator applies the formula for you.

The request and the delay

• The landlord must ask in writing. The request has no retroactive effect beyond three months before the month in which it is made.
• If the landlord forgets, they can ask later, but only the three previous months plus the following months are due.
• The landlord’s action to claim the indexation amount lapses one year after the registered letter requesting it.

The correction factor for E, F and G homes

A correction factor applies to the result of the formula when all three conditions are met:

1. the lease took effect before 14 October 2022;
2. the home’s EPB certificate is E, F or G;
3. the home is rented on the private or public market, including through a CPAS, a municipality, a social rental agency or the Régie Foncière. Homes let by public housing companies (SISP) and the Housing Fund are not affected.

The factor depends on the month of the lease anniversary and on the EPB class:

For a home rated E with an anniversary between 14 and 31 October, the indexed rent given by the formula is multiplied by 0.949447646. A lease that took effect on or after 14 October 2022 is not subject to this factor, but still needs registration and a valid EPB certificate. Indexation was restricted until 13 October 2023 and allowed again from 14 October 2023 with the adapted formula, as the ordinance of 13 October 2023 amended art. 224/2.

Indexation is not the same as rent revision

• Reference rent. The landlord must state the reference rent in the lease. It is not binding, but a rent more than 20% above it is presumed excessive. Since 1 May 2025, a tenant can ask for a review of an excessive rent, from the third month of a short-term lease of over one year, or the fourth month of a longer lease.
• Triennial revision (leases of nine years or more, at the end of each three-year period): either party can ask for a revision between the ninth and sixth month before the end of the period. A judge can grant it if the normal rental value, because of new circumstances, differs by at least 20% from the rent, or by at least 10% because of works paid by the landlord. An increase is due only if the lease is registered.
• Energy works. A rent increase for works by the landlord that improve energy performance or adapt the home for disability may be agreed, in writing, at the latest one month before the works start.

Which professional to consult

• The estate agent managing the lease, for the calculation.
• An EPB assessor if the certificate is missing or expired.
• A lawyer or the Justice of the Peace for a disputed indexation or revision.