Rent Calculator

Rent Calculator

What is rent indexation?

Every year, on the date on which the contract entered into force, the rent for your accommodation may be adjusted to the cost of living. Until December 1993, this indexation was always based on the fluctuations of the consumer price index. From January 1994 onward, the  health index became the mandatory basis.

Which lease agreements are eligible?

Signed Written lease agreement Oral lease agreement
Before 28th February 1991

Indexation if both parties provided this

Between 28th  February 1991 and  31st May 1997


After 31st May 1997 allowed except when excluded in agreement indexation not allowed


How is the rent indexation calculated?

The indexed rent =   basic rent (2) x new index (3)

initial index (1) (1)

  • The basic rent is the rent without possible costs and expenses owed by the tenant.
  • The initial index is that of the month preceding the date of the signature of the agreement (for all agreements that entered into force from 1st January 1984).
  • The new index is the health index of the month preceding the anniversary of the entry into force of the lease agreement (i.e. NOT the anniversary of the signature, unless both dates are the same).

 Calculate your rent yourself

The lease agreement entered into force 
before 1st January 1984
The lease agreement entered into force 
on or after 1st January 1984
agreement signed 
agreement signed 
between 1/01/1981 
and 31/12/1983
agreement signed 
agreement signed 
on or after

initial index

December 82 

initial index=

index of the month 
preceding the  
adjustment or entry 
into force of the 
agreement in 1983

initial index=

index of the month 
proceding the signature 
signature of the 

initial index=

health index of 
the month preceding 
the signature of 

basic rent = rent:

- set by court order 
- failing such court order, basic rent used in  
the calculation of the indexed rent in 1990 
- failing this, last rent paid in 1983.

basic rent =
 agreed rent

new index =
 the (health) index of the month preceding the anniversary of the entry into force of the agreement

Source: FPS Justice


More information

Although rent indexation has been a regional competence since the sixth state reform (1st July 2014), the old legislation remains in force until a community or a region decides to change the rules or to adopt new ones (

Thee brochure "The rent law", (available in Dutch and in French) published by the FPS Justice, remains applicable. The brochure covers all aspects of the private rent law. The rent indexation is also discussed in detail.

For questions on the indexation For questions on legal aspects

(FPS Economy) 
North Gate - Koning Albert II-laan 16 
1000 Brussels
Tel. : +32 [0]800 120 33 (9:00 - 12:00) 
e-mail :


Justice centres
For contact details