How do I file my Dutch tax return (aangifte) with the Belastingdienst?

Dutch residents file an annual income tax return (aangifte inkomstenbelasting) with the Belastingdienst. Most people file online via Mijn Belastingdienst at belastingdienst.nl, logging in with DigiD. The filing period typically opens in March, and the deadline for regular filers is 1 May. Extensions to 1 September (and beyond, for taxpayers using a tax advisor) can be requested.

For many salaried employees, the Belastingdienst sends a voorlopige aanslag (provisional assessment) and may pre-fill parts of the return based on employer data from the polisadministratie and bank data from financial institutions. You review, correct, and supplement the pre-filled information, adding any income not captured automatically (freelance work, Box 3 assets, foreign income).

If the tax due differs significantly from what was withheld at source, the Belastingdienst issues a final assessment (definitieve aanslag). Any balance due must be paid within six weeks of the assessment. Refunds are usually paid within a few weeks of filing.

Taxpayers who do not receive a filing invitation can still request to file voluntarily (ambtshalve aangifte). Self-employed workers (ZZP) and those with complex income always need to file.