How to estimate rental income before purchase
To estimate rental income before buying an investment property, use three complementary methods: compare with local listings on Immoweb, consult the Brussels rent grid (if applicable), and calculate based on a target gross yield of 4-5%. Factor in the EPC rating, property condition, and location.
Accurate rent estimation is essential for any property investment. Overestimating rent leads to unrealistic yield expectations, while underestimating means you might miss a good opportunity.
The three main estimation approaches:
- Market comparison: check similar properties listed for rent in the same neighbourhood
- Official reference grids: the Brussels indicative rent grid provides objective benchmarks
- Yield-based calculation: work backwards from the purchase price and your target gross yield
Key criteria affecting rent
| Criterion | Impact on rent |
|---|---|
| Location (city centre vs periphery) | +20% to +40% |
| EPC rating A-B vs E-F | +10% to +15% |
| Fitted kitchen | +5% to +10% |
| Terrace / garden | +5% to +10% |
| Parking included | +50 to +120 EUR/month |
| Number of bedrooms | Major factor for families |
| Renovation quality | +10% to +20% for recent renovation |
| Floor level (apartments) | +5% per floor (with lift) |
Check at least 10 comparable listings on Immoweb for similar properties in the same municipality. Remove the highest and lowest outliers and calculate the average — this gives you a realistic rent estimate.
Calculating gross rental yield
The gross rental yield formula:
Gross yield = (Annual rent / Purchase price) x 100
| Purchase price | Monthly rent | Gross yield |
|---|---|---|
| 200,000 EUR | 750 EUR | 4.5% |
| 250,000 EUR | 850 EUR | 4.1% |
| 300,000 EUR | 1,000 EUR | 4.0% |
| 150,000 EUR | 650 EUR | 5.2% |
In Belgium, a gross yield of 4 to 5% is considered standard. Above 5% is good, above 6% is excellent but often involves higher risk or lower-quality properties. Below 3.5% may indicate the property is overpriced for investment purposes.
Remember: net yield (after taxes, charges, vacancy, and maintenance) is typically 1.5 to 2 points lower than gross yield.
Regional specifics
Brussels-Capital Region
The Brussels indicative rent grid provides official reference rents based on location, surface area, number of bedrooms, condition, and EPC rating. While not binding, it is a reliable benchmark. Brussels rents are the highest in Belgium, with an average of approximately 950 EUR/month for a 2-bedroom apartment.
Wallonia
The Decree of 15 March 2018 does not provide an indicative rent grid. Walloon rents are generally 20-40% lower than Brussels. University cities (Liege, Namur, Louvain-la-Neuve) command higher rents.
Flanders
The Flemish Housing Rental Decree of 9 November 2018 does not cap rents. Flemish rents vary significantly between cities like Ghent, Antwerp, and Leuven (higher) and rural areas (lower). No official rent grid exists in Flanders.
Civil Code, article 1709 (freedom of contract). Brussels Ordinance of 27 July 2017 (indicative rent grid). No rent caps in any Belgian region for private leases.