The Dutch tax filing season for the 2025 tax year is now open. Whether you need to file a standard return (C-form), an arrival/departure return (M-form), or a provisional return (P-form), here are the key dates and deadlines you need to know.
Key deadlines for 2026
| Form type | Opens | Deadline | Who needs it |
|---|---|---|---|
| C-form (standard) | March 1, 2026 | May 1, 2026 | Residents for the full year 2025 |
| M-form (migration) | March 1, 2026 | July 1, 2026 | Arrived or left the Netherlands in 2025 |
| P-form (provisional) | March 1, 2026 | May 1, 2026 | Provisional assessment holders |
| Extension request | — | April 1, 2026 | Anyone needing more time (extends to September 1) |
First-time filers: If you arrived in the Netherlands during 2025, you'll likely need to file an M-form. This is more complex than the standard C-form and many expats benefit from professional help. See our M-form guide for details.
What you need before filing
- Your BSN (Burgerservicenummer) — required for all tax communications with the Belastingdienst.
- DigiD — the digital identity system used to log into the tax portal. If you don't have one yet, apply now at digid.nl — activation takes 3–5 business days.
- Annual income statement (jaaropgave) — your employer should provide this by March. It shows your gross salary, tax withheld, and social contributions.
- Bank statements — for claiming deductions and for Box 3 (savings and investments) reporting.
- 30% ruling decision letter — if applicable, you'll need this to claim the tax benefit on your return.
Common deductions expats can claim
- Mortgage interest — if you own a home in the Netherlands (Box 1 deduction).
- Study costs — tuition and training directly related to your current job (limited in 2025).
- Charitable donations — to qualifying Dutch or EU charities (must exceed threshold).
- Healthcare costs — extraordinary medical expenses above the threshold (eigen risico doesn't count).
- Commuting costs — public transport costs for commutes over 10 km (if not reimbursed by employer).
Tips to maximize your refund
- File early. The Belastingdienst pre-fills most data from your employer and bank. File early to get your refund faster — typical processing is 6–8 weeks.
- Check pre-filled data carefully. The tax authority may not have your 30% ruling details or foreign income. Always review and correct before submitting.
- Consider Box 3 optimization. If you have savings or investments, the new 2026 Box 3 rules may affect your tax. See our Box 3 tax guide.
- Use our estimator. Get a quick estimate before you file: Tax Return Estimator.
When to hire a tax advisor
Consider professional help if you arrived mid-year (M-form), have foreign income or assets, or have a complex situation with the 30% ruling. Most expat tax advisors charge €200–500 for a complete return and the cost is often recovered through deductions they identify.
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