How mortgage interest deduction works in Belgium - everything you need to know

How mortgage interest deduction works in Belgium This is an essential question for every Belgian homeowner. Mortgage interest deduction can significantly reduce your annual tax burden, but it is also one of the most complicated aspects of Belgian taxation. This guide gives you a complete overview of how the system works, what you can deduct and how to make the most of it.

What is mortgage interest deduction?

Mortgage interest deduction is a tax benefit available to homeowners. In other words, you can partially deduct the interest you pay on your mortgage from your taxable income. This reduces your net income tax.

This is an important distinction: you cannot deduct the full mortgage amount - only the interest portion. If you have borrowed €200,000 at 3% interest, that means €6,000 in interest per year. This €6,000 can (under certain conditions) be deducted.

The system differs by region

Belgium's three regions each have different rules on mortgage interest deduction. This is crucial - your benefits depend on where your property is located.

Flanders: no more mortgage interest deduction

In Flanders, mortgage interest deduction was completely abolished as of 1 January 2020. This was a radical change. Flemish homeowners can no longer deduct their mortgage interest from their taxable income. The measure sparked considerable political debate in Flanders - many critics felt the benefit primarily favoured higher-income homeowners.

The consequence: if you live in Flanders and took out a new mortgage after 2020, you are entitled to no mortgage interest deduction. This has made saving and investing relatively more attractive as alternatives.

Brussels: limited mortgage interest deduction

In Brussels, mortgage interest deduction still exists, but it is very limited and subject to ongoing changes. The current rules are complex and are adjusted every year. In principle you can deduct part of your mortgage interest, but:

• The amount is usually capped at a certain maximum (for example a percentage of your total income)
• It applies mainly to first homes (your family residence)
• Deducted interest is generally declared on your tax return

The exact figures change regularly, so getting up-to-date advice is genuinely necessary.

Wallonia: mortgage interest deduction retained

In Wallonia, mortgage interest deduction still exists, and the system is considerably advantageous. Walloon homeowners can use their mortgage interest as a tax deduction. Here is how it works:

You pay your mortgage interest to the bank. This interest can be deducted from your taxable income, which reduces your income tax. For many Walloon homeowners this is a significant benefit - sometimes several thousand euros per year.

How do you calculate the mortgage interest deduction?

Step 1: identify your interest component

Your first step is to determine how much interest you actually pay. Your bank provides this information annually in your statement. Your mortgage consists of two parts:

• Capital repayment - the amount you pay back towards the principal (NOT deductible)
• Interest - the amount you pay in interest charges (deductible, under certain conditions)

For example: your monthly payment is €1,000. Of this, perhaps €200 is interest and €800 is capital repayment. Over a year your total interest is therefore €2,400.

Step 2: check the conditions for your region

For Wallonia and Brussels - the regions where mortgage interest deduction still exists - specific conditions apply:

• It must relate to your family home - your primary residence where you actually live
• The mortgage must be for a property purchase - not for renovation or other purposes
• It must be a "recognised" mortgage - drawn up by a notary, not simply a personal loan
• You must have actually paid the interest - with proof to support it

Step 3: determine the maximum deduction

In Wallonia there is often no absolute ceiling - you can in principle deduct the full amount of interest paid. In Brussels, on the other hand, a maximum tax benefit may apply.

Example for Wallonia:

• You pay €6,000 in interest per year
• Your marginal tax rate is 40%
• Your tax benefit is approximately €2,400 (40% of €6,000)

You receive this benefit through a lower income tax bill.

Step 4: enter it on your tax return

On your annual tax return you declare the mortgage interest deduction. In Wallonia and Brussels there is usually a specific line or form for this purpose. You will need the following documentation:

• Interest statement from your bank
• Mortgage deed (copy)
• Notarial documents

Practical example: how the benefit works

Let us take a realistic example:

Walloon homeowner:

• Gross annual income: €50,000
• Mortgage interest paid during the year: €5,000
• Marginal tax rate: 40%
• Without deduction, income tax would be calculated on €50,000
• With deduction: taxable income falls to €45,000
• Tax saving: €5,000 × 40% = €2,000 per year

This means the bank is not the only party receiving your interest payments - you also get €2,000 back each year through a lower tax bill. Over 20 years that amounts to a total benefit of €40,000.

Flemish homeowner (new mortgage after 2020):

• Same situation
• Mortgage interest deduction: €0
• Tax saving: €0

This illustrates why the abolition in Flanders was painful for many homeowners.

Limits and exceptions

There are important limits to mortgage interest deduction:

Primary residence only

In most cases you can only deduct the interest on your family home. A second home, holiday property or investment property? That interest is generally not deductible.

Recognised mortgages only

Your mortgage must have been taken out via a notary and a registered financial institution. A private loan, even for a property purchase, does not qualify.

Interest rate conditions

The rules may have become stricter. In some situations - for instance with refinancing or restructuring - restrictions apply to what you can deduct.

Income ceiling

Some regions apply income limits. If your income exceeds a certain threshold, your deduction may be restricted.

Tips to maximise your mortgage interest deduction

1. Know the rules for your region

Check exactly which rules apply in your region. Wallonia, Brussels and Flanders differ considerably. A call to your local authority or tax office can clear up a great deal of uncertainty.

2. Keep good records

Keep your interest statements, mortgage deeds and notarial documents. The tax authorities can ask for proof. Poorly documented deductions may be refused.

3. Claim at the right time

If your mortgage is running and you benefit from the deduction, make sure you declare it every year. As you pay off your mortgage - and your interest decreases - your benefit will gradually shrink.

4. Compare mortgage structures

If you are taking out a mortgage, make sure you understand what the interest component is. Certain product types (for example fixed rate versus variable rate) can have an impact.

5. Seek tax advice

For larger mortgages or complex situations (shared ownership between partners, inheritance, second properties) advice from a tax specialist or accountant can save you thousands of euros.

The future of mortgage interest deduction

Mortgage interest deduction in Belgium is subject to political change. Flanders has abolished it; Wallonia and Brussels still maintain it - for now. Debates in parliament about simplification or further abolition arise regularly.

This means: keep an eye on the current rules on a regular basis. What is true today may be different next year.

Summary: how does mortgage interest deduction work?

• Flanders: mortgage interest deduction has been abolished (since 2020). No benefit remaining.
• Brussels: a limited mortgage interest deduction still exists, but it is capped. Check the current rules.
• Wallonia: mortgage interest deduction is available for family homes. You can deduct your interest from taxable income, which reduces your tax bill.

The calculation is straightforward: determine your annual interest payments, deduct them from your income and enjoy the tax benefit. But the conditions under which this is permitted are complex and vary by region.

Next step: make sure you get the most out of your benefit

Whether you are taking out a new mortgage or have been a homeowner for years - check that you are using all the deductions available to you. For many homeowners in Wallonia this can make a difference of thousands of euros per year. Make an appointment with a tax specialist or check your regional tax authority's website for the most up-to-date rules.

Also: if you are looking for the best mortgage terms and interest rates, compare mortgage offers from brokers and credit intermediaries. A better rate means lower interest to pay - and every fraction of a percentage point makes a difference!