Filing your 2025 tax return: what you need to know
In the spring of 2026, it's time to file your income tax return for the year 2025 with the Dutch Tax Authority (Belastingdienst). Whether you're employed, self-employed, or recently moved to the Netherlands, this guide walks you through the entire process step by step. We cover deadlines, required documents, deductions you shouldn't miss, and mistakes you'll want to avoid.
Deadlines: when do you need to file?
The Tax Authority sends out invitations to file in early March 2026. From that point, the pre-filled tax return is available in Mijn Belastingdienst.
Key dates:
- 1 March 2026 — Pre-filled tax return becomes available
- 1 May 2026 — Filing deadline (without extension)
- 1 September 2026 — Extended deadline (if requested)
Filing late without an extension? You risk a penalty of €385 per occurrence. Repeated late filing can lead to higher fines.
Tip: Request an extension through Mijn Belastingdienst well before 1 May if you know you won't make the deadline. It's free and gives you four extra months.
What do you need?
Gather these documents before you start. The better your preparation, the faster you'll be done.
For everyone
- DigiD — Required to log in to Mijn Belastingdienst
- Annual income statement(s) — From your employer(s), benefits agency, or pension fund
- BSN — Citizen service number (and your fiscal partner's)
- Bank details — IBAN for any refund
Home ownership
- WOZ assessment 2025 — Reference date 1 January 2024
- Annual mortgage overview — Interest paid and principal repayments
- Deemed rental value — 0.35% of the WOZ value (for properties between €75,000 and €1,330,000)
Medical expenses and donations
- Overview of specific medical expenses (not covered by insurance)
- Proof of donations to registered charities (ANBI institutions)
Self-employed or business owner
- Profit and loss statement 2025
- Balance sheet as of 31 December 2025
- Hours log (minimum 1,225 hours for the hours criterion)
- Investment overview for the Small Business Investment Deduction (KIA)
Tax brackets for 2025
Your income tax for 2025 is calculated using three brackets:
| Bracket | Income | Rate |
|---|---|---|
| 1 | Up to €38,441 | 35.82% |
| 2 | €38,441 — €76,817 | 37.48% |
| 3 | Above €76,817 | 49.50% |
Tax credits are subtracted from the amount owed: the general tax credit and the employment tax credit. These ensure your effective tax rate is lower than the table suggests.
Step-by-step: filing your return
Step 1: Log in and review
Go to Mijn Belastingdienst and log in with your DigiD. The Tax Authority pre-fills much of the information based on data from employers, banks, and insurers. Check everything carefully — errors in pre-filled returns happen more often than you'd think.
Step 2: Enter your deductions
This is where it counts. Go through every category: home ownership, medical expenses, donations, education costs, and business deductions if you're self-employed. The Tax Authority does not automatically fill in deductions for you.
Step 3: Review and submit
Check the summary with the calculated amount. Are you getting a refund or do you owe money? Verify all information is correct and submit. You'll receive a confirmation immediately.
Step 4: Wait for the assessment
The Tax Authority aims to issue a final assessment within three months. For refunds, the amount is deposited within six weeks after the assessment.
Deductions you shouldn't miss
Many people in the Netherlands leave money on the table by overlooking deductions. Here are the most important ones:
Mortgage interest
Paying mortgage interest? It's deductible up to the rate of the second bracket: 37.48% in 2025. On a €300,000 mortgage at 4% interest, that easily saves you over €4,000 per year.
Medical expenses
Specific medical expenses not covered by your health insurance can be deducted. This includes co-payments for medication, medical aids, prescribed diet costs, and travel costs to hospital. An income-based threshold applies.
Charitable donations
Donations to registered charities (ANBI institutions) are deductible. For regular donations, a threshold of 1% of your threshold income applies (minimum €60). Periodic donations (committed for five years) are fully deductible without threshold.
Education costs
Did you follow a course in 2025 for your current or future profession? Those costs are deductible above a €250 threshold. This includes tuition fees, books, and exam fees.
Self-employed deductions
If you meet the hours criterion (1,225 hours per year), you're entitled to:
- Self-employed deduction — €2,470 in 2025
- Starter's deduction — Additional €2,123 in your first three years
- SME profit exemption — 12.70% of remaining profit
Together, these deductions can save you thousands of euros per year as a freelancer. Check out our tax filing service for freelancers if you'd like help.
Common mistakes
We see these mistakes every year when reviewing tax returns:
1. Filing too late
The €385 penalty is easy to avoid. Mark 1 May in your calendar or request an extension.
2. Forgetting deductions
Medical expenses and donations are most commonly overlooked. Make a checklist and review every category. The Tax Authority does not fill in deductions for you.
3. Blindly trusting the pre-filled return
The pre-filled return regularly contains errors. Employers sometimes submit incorrect amounts, or data is missing. Verify every figure with your own records.
4. Not optimising fiscal partnership
Have a fiscal partner? You can divide certain deductions between you. Smart allocation can save hundreds of euros. Think about dividing mortgage interest deduction or the deemed rental value.
5. Reporting Box 3 incorrectly
Your assets in Box 3 are taxed based on a deemed return. In 2025, the tax-free allowance is €57,684 per person (€115,368 with a partner). The deemed return on savings is 1.37%, on investments 5.88%. Make sure you correctly report all assets and debts as of 1 January 2025.
When to hire an expert
Filing your own return is perfectly doable if you have a straightforward situation: employment income, possibly a home, and no special deductions. But in these situations, professional help is often worth the investment:
- Freelancer or business owner — The combination of business deductions, VAT, and bookkeeping makes the return complex. A mistake can cost you thousands. Check out our filing service for freelancers.
- Recently moved to the Netherlands — With an M-form or when you're taxable in multiple countries, the return becomes particularly complicated.
- DGA (director-major shareholder) — Optimising between your BV and personal income requires specialist knowledge.
- Filing after a death — An emotionally and administratively heavy task where you'll appreciate guidance.
- Major changes in wealth — Selling a home, receiving an inheritance, or large investment portfolios.
Not sure if you need help? Take our free tax check. We'll look at your situation free of charge and give you honest advice.
Summary
Filing your 2025 tax return doesn't have to be stressful. Prepare well by gathering all documents, take the time to review your deductions, and submit on time before 1 May 2026. Can't figure it out? The tax specialists at Jan de Belastingman are ready to help.
