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Definitieve aanslag

Final tax assessment

Last updated: September 28, 2026✓ Verified September 2026

What does Definitieve aanslag mean?

A definitieve aanslag is the final income tax assessment for a year. The Belastingdienst issues it after checking your return, and it settles the difference with any provisional assessment you already paid or received. The Belastingdienst normally has until 3 years after the end of the tax year to issue it. If you disagree, you have 6 weeks from the date on the letter to file a bezwaar.

Key facts

Issued within3 years after the end of the tax year (longer if you had a filing extension)
Objection deadline6 weeks from the date on the letter
Cost of objectingFree
Later correction by the tax officePossible through a navorderingsaanslag, up to 5 years

What to do

  • Compare it line by line with your return: income, deductions, box 3 assets and tax credits.
  • Look for a line stating the Belastingdienst deviated from your return (afwijking). That is where corrections are explained.
  • Check the result against your provisional assessment: extra to pay, or an extra refund.
  • If something is wrong, file a bezwaar within 6 weeks. It is free and can be done online.
  • Keep it for at least 5 years. You need it for mortgages, benefit checks and when you leave the country.

Worth knowing

If you find an error in your favour after the 6 weeks have passed, you can still ask the Belastingdienst to reduce the assessment ambtshalve (of its own motion). It is not a right, but it is accepted for clear mistakes within 5 years.

Frequently asked questions

How long does the Belastingdienst take to send the definitieve aanslag?

It varies from a few months to the legal limit of 3 years after the end of the tax year. Simple returns that match the pre-filled data are often settled quickly; returns with deductions or foreign income can take much longer.

What happens if I file a bezwaar?

The Belastingdienst reviews the assessment and sends a decision on your objection. If you still disagree, you can appeal to the court. Filing the objection does not automatically pause a payment, so ask for deferral (uitstel van betaling) in the same objection.

Can the Belastingdienst still change a final assessment?

Yes, within 5 years it can issue a navorderingsaanslag if it discovers new facts, such as undeclared foreign income or assets.

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