Rent calculators
Rent indexation in Flanders: index on the health index, from the rent the lease states.
A rent increase in Belgium is an indexation: Flanders indexes the original rent in the lease, never last year's figure, and nothing rises until you send a dated written demand. Forget a year and you recover three months of it, not twelve.
Letting law is written below the country here, so the rules differ inside it.
Belgium indexes the rent the lease states, excluding charges, never last year's indexed figure. Leave it empty to use the rent above.
It fixes the anniversary, and where an index applies, the starting index.
The anniversary you are claiming.
A poor rating blocks or dampens the rise in some places
The index for Aug 2023, the month before the lease start you gave. The lease should state it, with its base year.
The index for Aug 2026, the month before the anniversary, on the same base year.
Type the two index figures and the answer appears here. Dardaris holds no copy of the series, so it works from the figures you enter and shows them in the working.
What governs in Belgium, Flanders
- Index
- Gezondheidsindex (health index), base 2013 = 100
- Formula
- new rent = original base rent × health index of the month before the anniversary ÷ health index of the month before the lease was signed
Nothing is stored and nothing is sent. This runs the same calculation engine the product itself runs, in this browser.
What the rules actually say
The rules Dardaris applies in Flanders.
Every line below is read off the same jurisdiction pack the product runs on, and each one says whether anybody has confirmed it in a source.
- Index
Gezondheidsindex (health index), base 2013 = 100
Confirmed in Statbel
- Formula
new rent = original base rent × health index of the month before the anniversary ÷ health index of the month before the lease was signed
Always the ORIGINAL rent excluding charges, never last year's indexed rent. Both index values must be on the same base year.
Confirmed in a primary source
- Notice
A written demand is required
Indexation is not automatic in Belgium: it takes a dated written demand to the tenant. Nothing is owed until you send one.
Confirmed in a primary source
- Back claim
3 months can be back claimed
You can only claim back to the three months before the month your demand is sent. Forgetting a year does not accumulate, that money is gone.
Confirmed in a primary source
The questions that follow.
- How do you index a rent in Flanders?
- The new rent is the original base rent excluding charges, multiplied by the health index of the month before the anniversary and divided by the health index of the month before the lease was signed. Both values have to be on the same base year.
- Do I use the original rent or last year's indexed rent?
- The original rent stated in the lease, excluding charges. Using last year's figure compounds the increase and overcharges the tenant, and it is the most common error in Belgian indexation.
- Does indexation happen automatically?
- No. Belgium requires a dated written demand to the tenant, and nothing is owed until you send one. The date on that demand starts the back claim clock.
- What if I forgot to index for several years?
- You can claim back only to the three months before the month your demand is sent. Missed years do not accumulate: that money is gone.
The same calculator, under other law.
A rent rises differently in each of these, and the page for each one says how. Anywhere else, the calculator still runs on that jurisdiction's own pack.
The calculation takes a minute. The date is what costs you.
Nobody forfeits a year because the arithmetic defeated them. They forfeit it because the anniversary fell in a quiet month, the index was not out yet, and by the time it was, there was nothing to remind them.
- It watches the anniversary for youDardaris holds the lease, its reference quarter and its anniversary, and tells you a revision is due rather than waiting to be asked.
- And works it out on the right two figuresThe reference quarter the lease names, against the same quarter a year earlier, applied to the rent in payment. The DPE block and the twelve month window are part of the same answer.
- But it does not send itA letter that raises somebody's rent waits for you. Dardaris prepares it and says what it is based on, and you are the one who decides it goes.
The number is the easy part.
Dardaris keeps the lease, raises the invoice, matches the payment and writes down what it did. Bring one building and watch a month before you decide anything.
14 days before the first charge · Nothing is switched on until you say so