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Tax assessment notice: understand every amount of your tax

Updated on

Recalculate your tax assessment notice

The tax assessment notice (aanslagbiljet / avertissement-extrait de rôle) is the final calculation of your tax: it compares the tax due with the withholding tax already deducted. Any balance to pay is due within two months; a refund normally arrives within two months; you can lodge an objection for one year, starting from the third working day after the date of sending.

Copy in your taxable income and the balance: Indexo recalculates the tax line by line, checks the balance and prepares your due dates for your calendar.

What the tax assessment notice contains

SectionWhat you will findWhat to check
First pageThe balance: amount to pay or to be refunded, and the payment due date.Which way the balance goes and the due date.
Tax calculationEach partner’s taxable income, basic tax, tax-free amount, reductions, State tax, municipal tax.The income included and your family situation.
Withholding taxes and paymentsWithholding tax on earned and investment income, advance payments, tax credits (fiscal work bonus).The withholding tax on your 281 tax forms (code 286).
Legal noticeLegal basis, means of appeal, objection deadline.The date of sending: the objection period runs from the third working day after it.
The sections of the personal income tax assessment notice

The calculation page, line by line

Example for a single person with €30,000 of income taxable globally in 2026 and a municipal tax of 7%:

LineAmountExplanation
Income taxable globally€30,000.00Salaries after expenses, pensions, benefits, property income
Basic tax€9,516.50Scale: 25% up to €16,720, 40% up to €29,510, 45% up to €51,070
Tax on the tax-free amount− €2,887.50€11,550 tax-free, at 25%
State tax€6,629.00Split between federal tax and regional surcharges
Municipal tax€464.037% of State tax
Total tax€7,093.03Before withholding taxes and advance payments
Indexo estimate, scale for 2026 income

Next come the withholding taxes credited (code 286 on your tax forms 281.10), tax credits and advance payments. The balance is the difference.

Why do I have to pay? Why am I getting a refund?

Common reasons for having to pay

  • two employers, or a job and a benefit in the same year: each one deducted withholding tax as if it were the only one;
  • blue-collar holiday pay, benefits or a pension with too little withholding tax;
  • income with no withholding tax: a second home, a secondary self-employed activity without advance payments;
  • a lower marital quotient in the tax (€11,780) than in the withholding tax (€13,790).

Common reasons for a refund

  • a tax-free amount in the tax (€11,550) higher than the one in the withholding tax (€11,170) for 2026 income;
  • reductions that withholding tax ignores: pension savings, childcare, donations, service vouchers, an old mortgage loan;
  • an incomplete year: monthly withholding tax assumes twelve months of salary.

Deadlines and appeals

  • Paying: within two months, by the due date printed on the notice. If you have difficulties, ask for a payment plan before the due date.
  • Getting a refund: normally within two months after the notice is sent, into the account the tax authorities have on file.
  • Objecting: within one year from the third working day after the date the notice was sent (Article 371 of the Income Tax Code), via MyMinfin or in writing, giving your reasons. After that, ex officio tax relief remains possible for five years, under certain conditions.

Recalculate your tax assessment notice

Copy in the amounts from your tax assessment notice. Indexo recalculates the tax, checks the balance and prepares your due dates. Nothing is sent.

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Frequently asked questions

When will I receive my tax assessment notice?

A few months after your tax return, usually between the summer of the year you file and the middle of the following year.

My tax assessment notice does not match my simulation: what should I do?

First check the income included and your family situation on the calculation page. A difference often comes from a forgotten reduction or added income. If there is an error, lodge a reasoned objection within the year, counting from the third working day after the date of sending. If in doubt, contact FPS Finance or a tax adviser.

What is the municipal tax on my tax assessment notice?

It is a percentage of State tax, set by the municipality where you lived on 1 January of the tax year. Withholding tax assumes about 7%: a more expensive municipality means a little extra tax to pay.

What next?

Sources

Parameters in force on 1 October 2026. Each parameter links to its source, the official one where it exists; a secondary source is flagged as such.