The Dutch tax year runs from 1 January to 31 December, and the annual tax return (aangifte inkomstenbelasting) is filed with the Belastingdienst (Tax Authority). For most employees, this is a relatively straightforward process — your employer handles payroll taxes (loonheffing) throughout the year, and the annual return is largely a matter of confirming or adjusting the numbers. But there are several expat-specific considerations that can significantly affect the amount you owe or are refunded.
The Dutch tax system: boxes
Dutch income tax is organised into three "boxes." Box 1 covers income from employment and home ownership — this is where your salary sits, and where the progressive tax rates apply. In 2026, the rate is approximately 36.97% on the first €75,518 and 49.5% above that threshold. Box 2 covers substantial interests in companies (typically relevant if you hold more than 5% of shares in a company). Box 3 covers income from savings and investments, calculated as a deemed return on your assets above a threshold — this is the wealth tax that is most relevant if you have significant savings or investments.
Who needs to file
If you receive an invitation letter from the Belastingdienst (M-form for your first year, the standard aangifte form thereafter), you are required to file. Even if you do not receive an invitation, you are required to file if you had income from more than one employer, have deductible expenses, or expect a refund. Most expats with a single employer and no complex finances will either not need to file or will find the return very simple. If you are unsure, log in to Mijn Belastingdienst (using your DigiD) and check whether a pre-completed return is available — the system often pre-fills information from employer reports.
The M-form: your first year in the Netherlands
In the year you arrive in the Netherlands, you will receive the M-form (migrant form) rather than the standard return. This is because you were only resident in the Netherlands for part of the year, and your worldwide income needs to be declared and appropriately attributed. The M-form can only be filed on paper or via the belastingdienst.nl website — not through third-party tax software. It is more complex than the standard return, and many expats find it worth paying a tax adviser to handle this first return.
Deductions and allowances
Several deductions are relevant for expats. If you pay a mortgage on a Dutch property, the mortgage interest may be deductible under hypotheekrenteaftrek. If you have made charitable donations to ANBI-registered organisations, these may be partially deductible. Healthcare costs above a certain threshold (after deducting what your insurance covered) can be deducted. Study and professional development costs have become less broadly deductible in recent years, so check the current rules.
Partial non-resident taxation (with the 30% ruling)
If you have the 30% ruling and have opted for partial non-resident taxpayer status, your foreign Box 3 assets — savings and investments held outside the Netherlands — are not included in the Dutch wealth tax calculation. This can be a significant benefit if you have substantial foreign assets. The election must be made annually on your tax return and cannot be changed after the deadline.
Deadlines
The standard deadline for filing the annual return is 1 May following the tax year. If you need more time, you can request an extension via Mijn Belastingdienst, which typically grants an automatic extension to 1 September. If you use a recognised tax adviser (belastingconsulent), they can file under a professional extension arrangement that allows even later filing.
Getting help
For a straightforward employment situation with one employer and no major deductions, filing online via Mijn Belastingdienst is manageable for most people. The interface is available in Dutch only, but the forms are logical if you approach them systematically. For more complex situations — 30% ruling, foreign assets, self-employment income, or year-of-arrival M-form — a tax adviser with expat expertise is a worthwhile investment. The cost of professional filing (typically €200–€500 for a standard expat return) is usually outweighed by the deductions they identify.