Provisional Tax Assessment in the Netherlands 2026: What It Is and How to Apply

What Is a Provisional Tax Assessment?

A provisional tax assessment (voorlopige aanslag) is an advance amount set by the Dutch Tax Authority (Belastingdienst) before your final income tax return has been processed. Its purpose is to spread tax payments or refunds across the year, so you do not face a large lump-sum bill or wait months for a refund.

The Belastingdienst bases the provisional assessment on information it already holds: your income from the previous year, deductions you have previously claimed, and any request you have submitted yourself. In practice millions of residents in the Netherlands receive a provisional assessment each year, often without fully understanding what it entails.

Receiving vs. Paying: What Is the Difference?

There are two types of provisional tax assessment and it is important to understand the distinction:

• Receiving a provisional assessment (refund) – You receive money from the Belastingdienst each month. This happens when you are entitled to deductions such as mortgage interest relief, high medical expenses or other allowable deductions. Instead of waiting for the final assessment, you receive the benefit spread across monthly payments.
• Paying a provisional assessment (advance payment) – You pay tax to the Belastingdienst each month in advance. This is common for freelancers, self-employed professionals and anyone with income from which no payroll tax has been withheld, such as rental income or business profits.

Both types ensure you avoid a large surprise when the final assessment is issued.

What Does the Provisional Assessment Consist Of? IB and Zvw Explained

Your provisional assessment contains two separately calculated components:

• Income tax (IB – inkomstenbelasting) – Tax on your total income across box 1 (employment and home ownership), box 2 (substantial interest) and box 3 (savings and investments). The IB component factors in rates, tax credits and deductions.
• Health Care Insurance Act contribution (Zvw – Zorgverzekeringswet) – An income-dependent contribution towards healthcare insurance. In 2026 the rate is 5.32% on your contribution income up to approximately €71,628. Employees pay this through their employer, but self-employed workers and retirees receive a separate assessment.

Both amounts are listed separately on your assessment notice. The combined total of IB and Zvw determines your monthly payment or refund.

When Do You Receive an Automatic Provisional Assessment?

The Belastingdienst sends an automatic provisional assessment in the following situations:

• You received a provisional assessment last year and the Tax Authority expects a similar situation this year.
• You filed an income tax return that showed a balance due or a refund.
• The Tax Authority received third-party data (employer, benefits agency, pension fund) indicating a tax liability.

The automatic provisional assessment for 2026 is typically sent in November or December 2025, so that monthly payments or refunds start from January 2026.

How to Request or Modify a Provisional Tax Assessment

You can request a new provisional assessment or modify an existing one through Mijn Belastingdienst (mijn.belastingdienst.nl). The process is straightforward:

1. Log in with your DigiD.
2. Navigate to “Verzoek of wijzig voorlopige aanslag” (Request or modify provisional assessment).
3. Enter your expected income, deductions and personal situation for 2026.
4. The system calculates your new monthly amount immediately.
5. You receive the updated assessment notice within a few weeks.

It is advisable to modify your provisional assessment whenever your income changes – for example when you start a new job, lose your job, retire, or begin freelancing. This prevents an unexpectedly high additional charge or a long wait for your refund.

Example Scenarios: Who Gets What?

What If the Provisional Assessment Is Incorrect?

A provisional assessment is always an estimate. The definitive amount is only determined after your income tax return has been processed. If the amount is wrong, two actions are possible:

• Estimated too high? You are overpaying each month. Modify the provisional assessment via Mijn Belastingdienst. Any overpayment will be refunded with the final assessment.
• Estimated too low? You are underpaying. You will receive an additional charge on the final assessment, potentially with tax interest (in 2026: 7.5% for income tax). Adjust your assessment promptly to avoid this.

The Belastingdienst charges interest when the final assessment is imposed more than six months after the end of the tax year. File your return before 1 May of the year following the tax year to minimise interest charges.

Key Deadlines

• November/December 2025 – Automatic provisional assessment for 2026 is sent out.
• Throughout the year – You can request or modify a provisional assessment at any time.
• 1 March 2027 – Filing period for 2026 income tax return opens.
• 1 May 2027 – Deadline for 2026 return (unless an extension has been requested).

Need Help With Your Provisional Assessment? MOJKA Finance Can Assist

At MOJKA Finance in Rotterdam we help individuals and entrepreneurs request, verify and adjust provisional tax assessments. We ensure your monthly amount is accurate so you avoid surprises when the final assessment arrives. Not sure whether your provisional assessment is correct? Get in touch or complete your details via our income tax return form. As your expat accountant in Rotterdam, MOJKA Finance is here to help – contact us for a free consultation.