Cadastral income: the number behind every Belgian property tax bill

What cadastral income actually is

If you are arriving from a country where property tax follows the market — a periodic revaluation, a rateable value, a mill rate on assessed value — the Belgian system will feel strange, and it is worth understanding before you buy rather than after.

The cadastral income is the average net annual rental income a property would bring its owner, as estimated by the General Administration of Patrimonial Documentation — the "Cadastre", part of the federal finance service (SPF Finances / FOD Financiën). The official definition and its exact scope are set out on the federal finance service's cadastral income page.

Three things to grasp straight away:

• It is not a real rent. Even if you have never let your property, it has a cadastral income.
• It is not a tax. The cadastral income is never paid as such: what you pay is the property tax computed from it.
• It is attributed to plots and buildings, land included.

Where to find it

Three sources, depending on your situation.

• MyMinfin (myminfin.be), the federal tax portal. Log in with itsme, your eID or your digital key, then open the section covering your property. MyMinfin's menu labels change regularly, so look for the section about your home and your assets rather than a fixed wording. The non-indexed cadastral income of every property you hold a real right over appears there.
• The property tax assessment notice your Region sends every year mentions the property's cadastral income.
• The deed of purchase usually states it.

For a property that is not yours — one you are thinking of buying, typically — MyMinfin is no help: it only shows your own. Two routes remain: ask the seller, who can retrieve it in two minutes, or order a cadastral extract from the General Administration of Patrimonial Documentation.

A word of advice specific to newcomers: ask for the figure before making an offer, not at the notary's office. It is the only way to know what the property will cost you every year, and Belgian listings are not required to show it.

How it is set — and why 1975

The current cadastral income rests on the rental value of the property at an old reference date: 1 January 1975. In practice, for a dwelling, the administration estimates the annual rental value the property would have fetched at that time, using comparison points from that era, then deducts a lump sum for charges. For properties built or converted since, the figure is set by comparison with similar reference plots — still in 1975 values.

Why 1975? A general revaluation of every cadastral income in the country was meant to take place periodically. The last one was carried out with that reference date and has never been followed by another. Annual indexation exists to compensate for that missing revaluation.

The practical consequence matters when you are choosing between neighbourhoods: two properties worth the same on today's market can carry very different cadastral incomes, depending on what their area was worth in 1975. A gentrified district that was cheap fifty years ago may be taxed lightly; a once-desirable street that has not moved may be taxed heavily. It is a standing criticism of the system, and a reason always to check the actual figure rather than infer it from the price.

Indexed or non-indexed?

The figure shown on MyMinfin is the non-indexed one. Yet almost every tax calculation uses the indexed cadastral income: non-indexed × the year's coefficient. For 2026 property tax that coefficient is 2.3000, identical in all three Regions.

Mind the threshold trap. Some rules are assessed on the non-indexed figure — the €745 "modest dwelling" threshold is the one you are most likely to meet — and others on the indexed one. Always check which value a rule targets before concluding that you are above or below a threshold. Getting this backwards is the single most common mistake we see.

The link with property tax

The annual property tax is computed from the indexed cadastral income in three layers: a regional rate, then provincial surcharges (or agglomeration surcharges in Brussels) and municipal surcharges.

Local surcharges weigh far more than the regional rate: for the same cadastral income, the bill changes sharply from one municipality to the next. No national table can give you your property tax — the municipality is what decides it. Our guide to Belgian property tax walks through the full mechanism with a worked example.

Property tax is not the only levy sitting on this figure, and this is where foreign landlords are regularly caught out. If you let a dwelling to a private individual who does not use it for professional purposes, you are taxed in personal income tax not on the rent you actually collect, but on the indexed cadastral income increased by 40 %. That is a Belgian peculiarity with no equivalent in most countries, and it explains why a high cadastral income weighs twice on an investor.

When it changes: works, revision, objection

The cadastral income is not frozen. It is reviewed in three main situations:

• New build: the property must be declared when it comes into use. The Cadastre then sets the initial cadastral income and notifies it to you.
• Conversion: works that appreciably change comfort or surface area must also be declared, and can trigger an upward revision.
• Unfavourable change — partial demolition, lasting loss of a comfort feature: this can trigger a downward revision, also on declaration.

These declarations carry a 30-day deadline, running from the triggering event: coming into use for a new build, completion of the works for a conversion. The form and the list of works concerned are on the federal finance service's page.

Failing to declare is not free. A Royal Decree of 20 September 2023 sets a scale of fines, applicable per plot concerned: €1,000 where the cadastral income is below €745, €2,000 between €745 and €2,500, and €3,000 above €2,500.

Disagree with a cadastral income you have been notified of? You have two months from the notification to object, proposing an alternative figure yourself. This is the part to diarise the day the letter arrives. Once the window closes, the cadastral income is final until the property next changes: there is no late objection against a figure accepted ten years ago. The procedure is described on the same federal page.

Can it be reduced?

Not by a trick. A correctly set cadastral income, on an unchanged property, cannot be optimised. Three realistic routes exist, and they do not all target the cadastral income itself:

• Object at notification, within the two-month window, if the figure looks disproportionate compared with similar properties.
• Declare an unfavourable change to the property.
• Leave the cadastral income alone and reduce the property tax instead — the route that succeeds most often. Modest dwelling, dependent children, a person with a disability, involuntary vacancy: many of these entitlements are simply never claimed.

One clarification that avoids a common error: if the property has stood empty and unproductive, it is not the cadastral income that gets reduced but a proportional remission of the property tax that gets claimed — under strict conditions (Wallonia: involuntary vacancy of at least 180 days; Flanders: unproductiveness of at least 90 days). In Brussels that route is closed: since 2017, empty and unproductive properties are subject to property tax like any other.

Questions newcomers ask

Is this the same as the French valeur locative cadastrale or a UK rateable value?

It plays the same role — a notional rental value used as a tax base — but the resemblance stops there. The Belgian figure is expressed in 1975 values and merely indexed since, not periodically reassessed. That is why it can look absurdly low next to today's rents, and why the rates applied to it look high.

Does the cadastral income change if I renovate?

It can, if the works appreciably change comfort or habitable surface: those must be declared and can trigger a revision. Pure maintenance work does not in principle have the same effect, but the boundary is drawn by the administration — the federal finance service's page specifies what must be declared.

What is the difference between indexed and non-indexed?

The non-indexed figure is the base value set by the Cadastre, in 1975 values. The indexed figure is the non-indexed one multiplied by the year's coefficient — 2.3000 for 2026 property tax. It is the indexed figure that feeds the property tax calculation.

Can I find out the cadastral income of a property I want to buy?

MyMinfin only shows your own. Ask the seller for the figure, or order a cadastral extract from the federal finance service.

Is a high cadastral income a bad sign?

A higher figure means a higher property tax, and can cost you certain benefits tied to the €745 non-indexed modest-dwelling threshold. It says almost nothing about the property's current market value, however, since it is expressed in 1975 values.

Is it used for anything other than property tax?

Yes. It also feeds the taxation of property income in personal income tax, notably for second homes and for dwellings let to private individuals. Be careful: that context does not use the same indexation coefficient as property tax.

Official sources

These are the pages our figures come from. Belgian tax administrations publish in French and Dutch; there is no full English version of most of them, so a browser translation is often the practical way in.

• Revenu cadastral — SPF Finances (federal, French)
• MyMinfin — SPF Finances
• Précompte immobilier — SPW Finances (Wallonia, French)
• Onroerende voorheffing — Vlaamse Belastingdienst (Flanders, Dutch)
• Précompte immobilier — be.brussels (Brussels, French)