In Belgium, a landlord letting a garage or home is usually not taxed on the rent actually received but on a fixed, notional value: the cadastral income. Here is how it works in broad terms, with sources from the federal tax administration (FPS Finance).
This is general information, not individual tax advice. Our yield figures do not include income tax; ask an accountant or the tax office about your situation.
Cadastral income is a notional value the tax administration sets for every property. It corresponds to the average yearly net rental income, with 1 January 1975 as the reference. It is therefore unrelated to today's rent or market value. A garage has its own KI, separate from the home's.
On your tax return you enter the non-indexed KI; the tax office indexes it itself. The indexation coefficient is 2.1763 for income year 2024, 2.2446 for 2025 and 2.3000 for 2026. For personal income tax the assessment year is the income year plus one (assessment year 2026 therefore uses 2.2446); for property tax the assessment year equals the income year.
If you let the building to a natural person who does not use it for their profession, you declare the KI (code 1106/2106). The taxable amount is the indexed KI × 1.4 (indexed KI = KI × coefficient, rounded to the euro). The actual rent plays no part in this amount.
Official FPS Finance example: a KI of 450 euros gives 450 × 2.2446 = 1,010 euros indexed KI, and 1,010 × 1.4 = 1,414 euros taxable. That amount is added to your other income and taxed at the progressive rate. We do not calculate your tax and quote no rates.
If you let to someone who uses the building professionally, or to a company or association, you declare both the KI (1109/2109) and the gross rent (1110/2110). You are taxed on the higher of two amounts: the gross rent minus a flat 40% for costs, or the indexed KI × 1.4. The flat 40% deduction is capped at 2/3 of the non-indexed KI × a revaluation coefficient (5.63 for income year 2025; 5.75 for 2026).
Where letting is regular and professionally organised, all of it may count as business income. Where the line between managing private assets and professional letting lies is decided case by case by the administration; there is no fixed figure.
The owner pays property tax (onroerende voorheffing / précompte immobilier) every year on the indexed KI (coefficient 2.3000 in 2026), whether or not the property is let. In Flanders the base rate is 3.97% (the version of the Flemish Tax Code in force from 1 January 2026); in Wallonia and Brussels it is 1.25%. On top come surcharges from the province and the municipality (in Brussels also the agglomeration), which differ per municipality and can change every year.
For a garage with a low KI the amount is small: with a KI of 45 euros it is roughly 4 euros of base levy a year in Flanders, before surcharges. It is one of the yearly costs in our net yield.
The landlord must have a written lease registered. For an ordinary dwelling this is free and due within 2 months. For all other leases, including a parking space or garage, the deadline is 4 months and the fee is 0.2% of the total rent and charges over the lease term, with a minimum of 50 euros. FPS Finance example: (900 + 100) euros a month over 36 months is 36,000 euros, so 72 euros. With no written lease there is nothing to register.
Updated 27 October 2026; rules and coefficients change. This is general information, not individual tax advice. Our yield figures do not include income tax; ask an accountant or the tax office about your situation. PandPeil is an independent, free information project.