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Rent Indexation Calculator — Belgium 2026

Work out the legal indexed rent for a home in Flanders, Brussels or Wallonia with the official health-index formula, including the energy-label (EPC/PEB) correction that still applies to older leases. Index figures fill in automatically from 1994 to September 2026. Free, private, nothing leaves your browser.

1 · Where is the home?
2 · Energy label on the certificate
3 · Your lease
The rent written in the lease, without charges.
The start date in the lease. Each anniversary of this date is an indexation date.
In Brussels and Wallonia the start index is the month before signing. Leave empty if it was the same month.
To see how many months the landlord can still claim back (maximum 3).
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Indicative result for residential leases, not legal advice. Check it against your lease and the official regional calculator before you apply or pay an indexation.

Your rent, anniversary by anniversary

The health index, 1994 – 2026

base 2013 = 100 · monthly · Statbel

Every month at a glance

colour = change against the same month a year earlier · your two months are outlined

Guide — index a Belgian rent in under a minute

No account, no upload. Everything updates as you type, and the share link reopens the exact calculation.
1Pick the region

Flanders, Brussels or Wallonia. Since 2014 each region has its own rent law, and they disagree on details that change the result.

2Pick the energy label

The label on the EPC (Flanders), EPB (Brussels) or PEB (Wallonia) certificate. It only matters for leases that started before autumn 2022.

3Fill in the lease

The base rent written in the lease and the date it entered into force. In Brussels and Wallonia also the date you signed, if that was in an earlier month.

4Choose the year

Both index figures fill in from the built-in table and the new rent appears at once, with the formula written out.

5Check and share

Copy calculation gives you a ready-made line for a letter or e-mail; Share link lets the other party check the same numbers.

What the calculator shows

FORMULAThe legal maximum, with your numbers

Base rent × new index ÷ start index, written out with the actual figures and months, so anyone can check it in ten seconds.

ENERGY LABELThe 2022 correction, worked out

For older leases on homes with a poor label, the correction factor is calculated for you — the same figure as the official Brussels table, and the official Flemish and Walloon method.

TIMELINEEvery anniversary since the start

A chart and a table with the rent for each year of the lease, with and without the energy-label correction.

BACK PAYWhat can still be claimed

Enter the date of the written request and see from which month the new rent applies and how much back pay is due — never more than three months.

INDEX DATA32 years of health index

Every month from January 1994 to September 2026, as a chart and as a colour grid, with your start and new month highlighted.

PRIVATENothing is sent anywhere

Rent, dates and address details stay in your browser. The page keeps working offline once it has loaded.

How rent indexation works in Belgium

A residential rent in Belgium may be adjusted to the cost of living once a year, on the anniversary of the date the lease entered into force. The adjustment follows the health index (gezondheidsindex / indice santé) and the law sets a ceiling:

new rent = base rent × new index ÷ start index

  • Base rent — the rent written in the lease, without charges. Always start from this amount, never from last year's indexed rent.
  • New index — the health index of the month before the anniversary. Indexing on 1 July uses the June figure.
  • Start index — in Flanders the health index of the month before the lease entered into force; in Brussels and Wallonia the month before the lease was signed.

Example: a lease that started on 1 July 2021 in Flanders at €800.00 a month. The start index is June 2021 (111.31) and for the 2026 indexation the new index is June 2026 (139.08). The new rent is €800.00 × 139.08 ÷ 111.31 = €999.59.

Why you never index last year's rent

The new index already contains every year of price increases since the start of the lease, so the formula always works from the original base rent and the original start index. Indexing an already indexed rent counts inflation twice; it looks harmless in the second year and is clearly wrong by the sixth. It is the most common mistake landlords make. The second most common is using the index of the anniversary month itself instead of the month before.

The health index

The health index is the consumer price index without alcoholic drinks, tobacco and motor fuel (except LPG). Statbel publishes it monthly since January 1994, around the end of each month. Rent uses the ordinary monthly health index — not the four-month smoothed index used for wages and benefits. This calculator uses one series throughout, base 2013 = 100. Statbel also publishes the figures in base 2025 = 100 since January 2026; they look about a quarter lower. Both figures in the formula must come from the same base: a base-2013 start index with a base-2025 new index would understate the rent by about 26%. Since only the ratio matters, a correct calculation gives the same result in either base, give or take a cent of rounding.

Energy labels and the correction factor

During the 2022 energy crisis each region decided that landlords of poorly insulated homes should not fully benefit from the index for a year. That temporary freeze has ended everywhere, but for leases that already existed it left a lasting trace: the year that was skipped is not caught up later.

RegionLease in force beforeFreeze window (anniversaries)Indexation allowed in the window
Flanders1 Oct 20221 Oct 2022 – 30 Sep 2023EPC A+–C 100% · D 50% · E, F, no EPC 0%
Brussels14 Oct 202214 Oct 2022 – 13 Oct 2023EPB A–D 100% · E 50% · F, G 0%
Wallonia1 Nov 20221 Nov 2022 – 31 Oct 2023PEB A–C 100% · D 75% · E 50% · F, G, no PEB 0%

Since the window closed, every later indexation of such a lease carries a correction. In Flanders and Brussels the standard result is multiplied by a correction factor; in Wallonia the reduced rent from the window becomes the new base rent, with the index of that anniversary as the new start index. The three methods come down to the same calculation:

factor = p + (1 − p) × index before the previous anniversary ÷ index before the anniversary in the window

where p is the share of indexation that was allowed (0.5 for 50%, 0 for none). In the example above with EPC label F, the window anniversary was 1 July 2023: the factor is June 2022 ÷ June 2023 = 121.02 ÷ 127.09 = 0.9522, so the rent becomes €999.59 × 0.9522 = €951.85, €47.74 a month less than without the correction. For Brussels this formula reproduces the official table of correction factors on be.brussels to the ninth decimal.

  • Flanders — the factor stays until the landlord obtains a new EPC with label A+, A, B or C, or a new lease starts. In November 2024 the Flemish government announced that homes with label E or F would not be indexed at all from 2028; check whether that has been enacted before relying on it.
  • Brussels — the factor applies to E, F and G; a valid EPB certificate must have been given to the tenant. This calculator treats a missing certificate like F/G.
  • Wallonia — the PEB label has no effect on leases that started after the window, and A–C were never affected.

When can the rent be indexed?

  • A written lease. Indexation is the legal default for a written residential lease. It needs no clause; only an explicit exclusion stops it. The parties may agree on less, never on more than the formula.
  • A registered lease in Brussels and Wallonia, where registration is an explicit condition. Registration is compulsory and free everywhere and is the landlord's job.
  • A written request. Indexation is never automatic: the landlord (or the tenant, if the index has fallen) must ask for it in writing. An e-mail can do; registered post is safer if a dispute is likely.
  • Once a year, from the anniversary. Not on 1 January for everyone, and not twice a year.
  • At most three months back. A late request works back at most three months before the month of the request. A landlord who forgets for three years loses the back pay for all but three months, but from the request on the rent is at the full indexed level. Enter the request date in the calculator to see the exact months.

What if the index falls?

The formula is a ceiling, so if the health index drops, the indexed rent drops too — but only if someone asks for it in writing. In practice that is the tenant.

Checking a landlord's letter

A correct indexation can be explained in one line: base rent, two index figures, two months and, where it applies, the correction factor. If a letter gives only a new amount, ask for that line and compare it with the formula here. You can refuse an indexation on legal grounds only — an unregistered lease where registration is required, the wrong months or index, a missing correction factor, or more than three months of back pay. Disagreements go to the justice of the peace (vrederechter / juge de paix) where the home is; a tenants' association or a mediation service usually settles an arithmetic dispute first.

Other kinds of lease

Short leases of three years or less are indexed in the same way. Commercial leases follow the federal law of 1951: they can only be indexed if the lease has an indexation clause, and the energy-label correction does not apply. Social housing rent is based on income and is not indexed this way. Student and co-housing leases have their own regional rules. A furnished let that is the tenant's main home follows the normal residential rules; holiday lets do not.

Sources

Health index: Statbel. Energy-label rules: Vlaanderen.be, be.brussels and wallonie.be. This page is an indicative tool, not legal advice; rent law changes, so check the official regional source when money is at stake.

More tools

See how prices and pay moved with the salary inflation calculator, compare Belgian net salaries with the net salary comparator, or work out a loan with the loan calculator.