How do you calculate gross rental yield?

Gross rental yield is annual rent divided by the total purchase cost, times 100. For example, a 150,000 euro apartment let at 750 euros a month earns 9,000 euros a year, a gross yield of 6.0%. Belgian gross yields commonly run 3.5% to 5% in cities (estate-value.be, 2026), higher in Charleroi.

Gross rental yield is the simplest performance gauge for a rental property. The formula is: (annual rent divided by the all-in purchase price) multiplied by 100. Annual rent is the monthly rent times twelve; the purchase price should ideally include acquisition costs to be realistic, though many quick estimates use the headline price alone.

A worked example: buy an apartment for 150,000 euros and let it at 750 euros a month. Annual rent is 9,000 euros, so gross yield is 9,000 divided by 150,000, which is 6.0%. If you include the roughly 12.5% Walloon registration duties on an investment purchase (wallonie.be, 2025) plus notary fees, the all-in cost rises to about 170,000 euros and the honest gross yield falls to around 5.3%.

Gross yield is useful for fast comparison between properties but it flatters the return, because it ignores every running cost. Belgian city gross yields typically sit in the 3.5% to 5% band (estate-value.be, 2026), while low-price Charleroi can reach 6% to 8% (immoabita.be, 2025) and pricier Namur or Neupre sit lower.

The point investors miss: a high gross yield on a cheap property can shrink dramatically once costs and rental vacancy are counted, so gross yield should never be the final word. Use it to shortlist, then compute net yield before you commit. Two properties with the same gross yield can deliver very different net returns depending on charges, management and how quickly they let.

At a glance

Registration duties on an investment purchase: 12.5% in Wallonia (wallonie.be, 2025).