M form — when and how do I fill it in?
The M form is mandatory for the year you moved to or from the Netherlands: (1) Application year: calendar year of immigration or emigration. Arrived March 2025: file for 2025 (deadline 1 May 2026). (2) Who must: anyone partial-year tax resident. Applies to expats, returnees, graduates abroad. (3) Apply: Tax Office auto-sends with filing invitation. Not received? Request via belastingdienst.nl > M form (DigiD needed). Paper form also possible (extra wait). (4) Processing time: 6 months from receipt (vs. 3 mo for regular). Up to 12 mo if complex. (5) Often refund: ~€1,000-5,000 for expats earning <12 mo in year. Tax advisor (cost €200-600) often saves €1,000+ extra. (6) No filing = fine up to €385 + later assessment.
Step by step
- 1Check if you receive an M formTax Office auto-sends between 1 March and 1 April to BRP address. Not received? Request via belastingdienst.nl > Filing > M form.
- 2Gather income dataAnnual statement NL employer + abroad, bank balances 1 Jan + 31 Dec, mortgage papers, daycare costs, medical costs. Expats: 30% decision, residence-address changes.
- 3File online or paperOnline via Mijn Belastingdienst (DigiD) = faster (~3 mo). Paper version = 6 mo+. Complex cases: tax advisor (NOB member) finishes in 1-2 weeks.
- 4If unfamiliar with system: advisorFor 30%-ruling recipients + foreign pension rights + double tax treaty: tax advisor ~€300-600. Often pays for itself via missed deductions + smarter pension contributions.
- 5Wait for outcome + refundTax Office processes M form in 6 mo from receipt (vs 3 mo regular). On refund: bank transfer. On assessment: payment plan up to 24 mo standard.
All contacts
Frequently asked questions
How long until I get my refund?
Standard 6 months after filing (vs 3 mo regular). Online via DigiD often faster (~3-4 mo). Complex (30% ruling + double tax): up to 12 mo. Delay >6 mo: send formal notice.
What if I miss the filing?
No response within 14 months after request: official assessment (Tax Office estimates). Often unfavorable. Fine up to €385 possible. Better late than never — later appeal is possible.
Can my employer do the filing for me?
Some international employers offer expat tax service (PwC, Deloitte as perk). Employer pays advisor. Personal items like mortgage not always included — ask specifically.
What does a tax advisor cost for M form?
Simple expat return: €200-400. With 30% ruling + double tax: €400-800. NOB members more expensive but quality assurance. ROI often positive: missed deductions like medical or education costs.
What if I got 30% ruling mid-year?
M form handles this standard. Calculate: salary before 30% ruling fully taxed, salary from decision date with 30% relief. Tax advisor can optimize for maximum refund (avg €1,500 extra).
Need M form if I left in December?
Yes. Even 1 day NL tax resident = M form mandatory. For year of departure: full return on income until departure date. Pension rights + ongoing insurances carry over to new country.
Sources
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