Tax return in the Netherlands: deadlines, M-form and refunds

Table of contents

Who must file a Dutch tax return?

You are required to file if the Belastingdienst sends you an invitation letter (aangiftebrief), or if you know you owe more than €56 in tax. The letter usually arrives in January or February. Ignoring it is not an option, even if you believe you owe nothing.

When filing voluntarily makes sense

No letter does not mean no benefit. Filing voluntarily is usually worth it if you started or stopped working partway through the year, bought a home with a mortgage, had high healthcare costs, or have a fiscal partner with little or no income. You can file voluntarily up to 5 years back, so a refund from your arrival year is often still claimable.

Deadlines and extensions for 2026

The return you file in 2026 covers tax year 2025. A persistent expat myth says the deadline is 1 April; the real deadline is 1 May. The 1 April date matters for a different reason: file before it and the Belastingdienst guarantees an answer before 1 July.

How to file your Dutch tax return step by step

1. 1
   Get your DigiD ready. You need a BSN and activated DigiD to log in. Requesting a DigiD takes about 5 days, so do not leave this until late April.
2. 2
   Collect your documents. Your jaaropgaaf (annual income statement from each employer), bank and investment balances on 1 January, mortgage statement (if you own), and healthcare cost receipts.
3. 3
   Log in to Mijn Belastingdienst at belastingdienst.nl and open "Aangifte inkomstenbelasting". Salary, bank balances and mortgage data are usually pre-filled. Your job is to check them and add what is missing.
4. 4
   Check the fiscal partner allocation. If you have a fiscal partner, you can shift shared deductions between you. Allocating mortgage interest to the higher earner often increases the combined refund by hundreds of euros.
5. 5
   Review the outcome and submit. The portal shows your refund or amount due before you sign. The final assessment (definitieve aanslag) follows by post and in your Berichtenbox.

What makes the M-form different

The M-form (M-biljet, M for migration) applies to the year you moved to or from the Netherlands. It splits the year into a resident period and a non-resident period, each with its own rules. You cannot use the standard online P-form for that year; the system routes you to the M-form automatically based on your BRP registration dates.

The M-form had a fearsome reputation: a 50-page paper booklet, in Dutch only. Since 2021 it can be filed online through Mijn Belastingdienst like a normal return, which removed most of the pain. The online version skips the sections that do not apply to you.

Why the M-form usually means a refund

Dutch payroll tax tables assume you earn your monthly salary for all 12 months. If you arrived in August and earned five months of salary, too much was withheld relative to your actual annual income. The M-form corrects this, which is why most migration-year filers get money back. Waiting times are longer than normal returns: expect 6 months to a year for the assessment.

A refund happens whenever more tax was withheld from your salary than you actually owe for the year. These are the most common expat situations:

• Partial working year: you arrived, left, or had months between jobs. The classic M-form refund, typically €500-€2,500.
• Mortgage interest: homeowners deduct mortgage interest on their primary residence. See our guide on buying a house in the Netherlands.
• Fiscal partner with low income: shifting deductions to the higher earner and using the partner's unused tax credits.
• Deductible costs: specific healthcare costs not covered by insurance, charitable donations, and alimony payments.
• Multiple employers: two jobs in one year often means both applied the general tax credit, which the return corrects in either direction.

Get your refund monthly instead: the voorlopige aanslag

If you expect the same refund every year (typical for homeowners), you can request a provisional assessment (voorlopige aanslag) and receive the refund in monthly instalments during the year. It improves cash flow but is an estimate: if your situation changes, you settle the difference after filing.

Refunds are separate from monthly benefit payments like zorgtoeslag and huurtoeslag, which run through a different system. Check our Dutch allowances and benefits guide to see what you can claim on top of your tax refund.

Dutch income tax divides income into three boxes. Box 1 covers employment and home ownership, Box 2 covers substantial shareholdings (5% or more of a company), and Box 3 covers savings and investments. The return you file in spring 2026 uses the 2025 rates; the 2026 rates apply to income you earn this year.

Box 1 rates on employment income

These are the rates before tax credits (heffingskortingen), which reduce the actual tax for most incomes. To see what lands in your bank account each month, use our net salary guide. If you have the 30% ruling, a large slice of your gross salary is tax-free, which changes every number above; our HSM visa and salary guide covers the thresholds.

Box 3: savings and investments

Box 3 taxes a notional (assumed) return on your worldwide assets above the tax-free threshold: €57,684 per person for 2025 and €59,357 for 2026 (double for fiscal partners), at a 36% rate on the assumed return. After the court rulings of recent years you can object if your real return was lower. The details matter for anyone with meaningful savings or investments; see our dedicated Box 3 wealth tax guide and, for portfolio decisions, the investing in the Netherlands guide.

Deductions expats often miss

• Mortgage costs in the purchase year: beyond interest, one-off costs like the mortgage advisor, valuation and notary mortgage deed are deductible in the year you bought.
• Specific healthcare costs: certain expenses your insurer did not cover (some treatments, aids, diets on prescription), above an income-based threshold.
• Charitable donations: gifts to registered charities (ANBI status) above 1% of your income; periodic donations fixed for 5 years are deductible from the first euro.
• Pension gap contributions (jaarruimte): voluntary contributions to a lijfrente product if you built up too little pension, common for expats with foreign career years.
• Partner allocation: not a deduction itself, but allocating deductions to the higher-earning fiscal partner is the single most overlooked optimization.

Note what is not deductible anymore: study costs (abolished in 2022, replaced by the STAP scheme which has itself ended) and commuting costs for employees (handled via employer allowances instead).

DIY or tax advisor: what should you pay for?

An advisor who finds one missed deduction or fixes one partner allocation usually covers their own fee. Our expat tax advisors comparison lists English-speaking firms with prices and specializations, including M-form specialists.

Official resources

• Belastingdienst English pages: official information for non-resident and international taxpayers, including the M-form.
• Government.nl income tax overview: how the Dutch income tax system and boxes work.
• Belastingdienst English phone line: +31 555 385 385 (Belastingtelefoon Buitenland) for questions in English.

Frequently asked questions