Belgian personal income tax calculator in Excel

What does this tool do?

Who is it for?

• Employees who want to know how much tax falls on their salary and why the final bill differs from the withholding tax on their payslip.
• Anyone considering a pay rise, a new job or extra income who wants to see what is left after tax.
• Self-employed people with a sole proprietorship who want an indication of the income tax on their profit before talking to their accountant.
• Students and newcomers who want to understand how tax brackets, the personal tax allowance and municipal tax work together.

What is included?

• Input sheet with gross annual salary or taxable income, the choice of assessment year and the municipal tax rate of your municipality.
• Parameter sheet with the tax brackets, the personal tax allowance and the cap on flat-rate professional expenses for assessment years 2026 and 2027, with sources.
• Calculation per bracket: how much income falls in each bracket and how much tax each bracket produces.
• Overview sheet with basic tax, the reduction for the personal tax allowance, municipal tax, total tax and the average and marginal tax rate.
• Chart showing which part of your income falls in which bracket.
• Family situation, dependent children, actual professional expenses and a comparison of two scenarios (extended version).

How do you use the file?

1. 1

   Open the file and go to the “Input” sheet. Only the yellow cells are meant to be filled in; every other cell contains a formula.

2. 2

   Choose the assessment year from the dropdown: assessment year 2026 for income earned in 2025, assessment year 2027 for income earned in 2026. The file pulls the matching brackets and amounts from the parameter sheet.

3. 3

   Enter your gross annual salary (the total of your payslips, before social security contributions and withholding tax). If you are self-employed, enter your net taxable income and set the social security line to zero.

4. 4

   Keep the flat-rate professional expenses, or choose actual expenses in the extended version and enter the amount you can prove.

5. 5

   Enter the municipal tax rate of your municipality. You find it in the list published by FPS Finance or at the bottom of your last tax assessment notice.

6. 6

   Look at the “Overview” sheet: it shows the tax per bracket, the reduction for the personal tax allowance, the municipal tax and the total. Compare it with the withholding tax on your payslips to estimate whether you will pay extra or get a refund.

Worked example

A single employee without dependent children, assessment year 2026 (income 2025), with a taxable income of €45,000. That is what remains after the social security contribution and the flat-rate professional expenses (maximum €5,930) have been deducted from gross salary. The municipal tax of 8 % is an assumption.

Every extra euro above €45,000 falls in the 45 % bracket and, with 8 % municipal tax, costs 48.6 cents in tax. That is the marginal rate, well above the average rate of 32.7 %. On the tax assessment notice, the withholding tax already deducted from your salary is then subtracted.

Sources & calculation method

This is how the calculation is built:

1. From gross to taxable: the employee social security contribution comes off gross salary first (13.07 % for employees: 7.50 % pension, 3.55 % and 1.15 % health and disability insurance and 0.87 % unemployment, according to the administrative instructions of the NSSO). The file then deducts the flat-rate professional expenses: 30 % with a maximum of 5,930 euros for assessment year 2026 and 6,070 euros for assessment year 2027. What remains is the taxable income.
2. Brackets: the taxable income is spread over the brackets of the chosen assessment year. For assessment year 2026: 25 % up to 16,320 euros, 40 % from 16,320 to 28,800 euros, 45 % from 28,800 to 49,840 euros and 50 % above that. For assessment year 2027 the limits are 16,720, 29,510 and 51,070 euros. The sum of the tax per bracket is the basic tax.
3. Personal tax allowance: it is not deducted from income but converted into a reduction. The tax that would be due on the amount of the allowance (10,910 euros × 25 % = 2,727.50 euros for assessment year 2026; 11,180 euros for assessment year 2027) is subtracted from the basic tax. In the extended version, dependent children increase the allowance by the amounts in the parameter sheet.
4. Reductions: in reality, tax reductions follow next, such as for pension savings, donations or service vouchers. The file deliberately does not calculate them; the result is an indication of the tax before reductions.
5. Municipal tax: your municipality levies a percentage of the personal income tax. The file applies the rate you enter. According to the FPS Finance list for assessment year 2026, that rate ranges from 0 to 9 %; 8 % is the most common and roughly three in four municipalities sit between 7 and 8.5 %. The total, minus the withholding tax already deducted, is what you pay extra or get back.

Assumptions

• The file uses the rates and amounts published by FPS Finance for assessment year 2026 (income 2025) and assessment year 2027 (income 2026). Check the parameter sheet after a new indexation.
• The 13.07 % social security contribution applies to private-sector employees. Self-employed people enter their net taxable income, after social contributions and professional expenses, as their accountant calculates it.
• Municipal tax is the rate you enter; the example uses 8 %. Check the exact rate of your municipality in the official list.
• All income is treated as jointly taxable professional income. Income taxed separately, such as certain allowances or income from the sharing economy, is not covered.

Limitations

• The short version calculates for one person: no marital quotient, no dependent children and no joint return. The extended version adds dependent children and the family situation, but remains a simplification.
• Tax reductions such as pension savings, donations, service vouchers or the housing bonus are not included; the result is an estimate, not a tax assessment notice.
• The file does not replace Tax-Calc or MyMinfin: for a complete provisional calculation with all your codes, use the applications of FPS Finance.

Sources

This page and the file were last updated on September 24, 2026. Legislation and rates may have changed since.

Frequently asked questions