Everything you need to know about personal income tax as a self-employed person

What is personal income tax? 🔎

Everyone adult Belgian is taxed on his/her worldwide annual income yearly through personal income tax.

For this, you have to share your income yearly with the tax authorities so that they can determine how much taxes you owe the state. You do this via your tax return.

If you have a sole proprietor (secondary occupation, main occupation or self-employed student), the income from your business is also considered personal income. You then also pay personal income tax on the sum of your income as an employee and the profits from your business.

Personal income tax return 📝

Tax-On-Web (accessible via MyMinfin) is the easiest way to do your tax return . Both online and on paper, your return will consist of Part 1 which is required for everyone and Part 2 which you only need to fill in if you are a sole proprietor.

Sometimes you will receive on email or letter a proposal of simplified declarations. If you carry on a self-employed activity, the simplified declaration proposal will never be correct and you will therefore still have to fill in the details of your self-employed activity….

Calculating personal income tax 🧮

As a self-employed person with a sole proprietor (in secondary occupation or as a self-employed student), your income as an employee is simply added to the profit from your business to calculate personal income tax. So you are taxed on the sum of both.

For personal income taxes, Belgium works with a progressive system. This means that you are taxed more heavily on each higher tax bracket than on the previous one. Below is a summary of all tax brackets for income in 2026 (assessment year 2027):

Income bracket % taxes
From € 0 to € 16,720 25%
From € 16,720 to € 29,510 40%
From € 29,510 to € 51,070 45%
From € 51,070 and above 50%

In addition to these tax brackets, there is also a tax-free amount to which every Belgian is entitled every year. You do not pay taxes on this amount. For the 2026 income year (assessment year 2027), this amount is €11,550. You can also calculate this in our (simplified) taxes calculator tool for self-employed people.

In practice you therefore pay no tax on the first €11,550 of your income. Technically it works as a reduction, because the tax-free allowance is set off against your lowest income brackets under article 134 of the Belgian income tax code, which gives everyone the same benefit of €2,887.50 instead of one that follows your highest rate. This tax-free amount can still be increased depending on your personal situation (dependent children, for example).

Advance payment of personal income tax

The advance payment on personal income tax often raises many questions.

The idea is fairly simple. To avoid the government receiving income only at the end of the year, you can pay part of your taxes in advance.

As an employee, this will be automatic, as your employer deducts part of your salary as withholding tax. These are then paid directly to the government as an advance on your taxes.

If you are self-employed, things run a little differently. Then you will be able to make advance payments on personal income tax every quarter, based on the profits from your business.

Although advance payments as a self-employed person are not required, the government still encourages them. From the 2026 income year onwards the increase for making no or insufficient advance payments has been abolished for self-employed people who earn profits or professional income, so you no longer face a surcharge if you pay nothing in advance. The bonification does remain, which means paying voluntarily still works in your favour.