An estimate of this year's tax, paid in advance in instalments. If the estimate is wrong, you change it yourself.
In short
A voorlopige aanslag (provisional assessment) is an estimate of the Dutch income tax you will pay or get back for a year. The Belastingdienst, the Dutch tax office, often sends one unasked, based on an earlier year; you can also request one yourself in Mijn Belastingdienst. You pay the current year in one go, at the latest one month after the date on the assessment, or in up to eleven monthly instalments. As a business owner you also get a separate provisional assessment for the Zvw contribution. After your tax return, what you already paid is settled against the final assessment. If you earn more or less than the estimate, change it: usually until 1 May of the following year, or until the date in your tax return letter. You cannot object to a provisional assessment; you can change it.
An estimate of your income tax for a year, settled against the final assessment after your tax return.
Paying
In one go at the latest one month after the date of the assessment, or in up to 11 monthly instalments; the last one before the end of the year.
Changing it
In Mijn Belastingdienst, with DigiD. Usually until 1 May of the following year; with a tax return letter, until the date in it.
Zvw contribution
As a business owner you get a separate provisional assessment for the Zvw. You change it the same way.
Objection
Not possible against a provisional income tax assessment: you change it instead.
Example: you earn more than your provisional assessment assumes
Your provisional assessment for 2026 is based on your 2024 figures, when you made € 30,000 profit. This year you expect € 45,000. The profit figures are made up; the tax is calculated with the net income calculator on this site, with the same assumptions: hours criterion met, no other income, no tax partner.
Example: you earn more than your provisional assessment assumes
At € 30,000 profit
≈ € 791 income tax and ≈ € 1,219 Zvw contribution
At € 45,000 profit
≈ € 5,557 income tax and ≈ € 1,855 Zvw contribution
If you change nothing
After your 2026 tax return you pay about € 5,401 extra in one go: € 4,766 income tax and € 635 Zvw
Instalments (example from the Belastingdienst)
An assessment of € 1,210 dated 28 January 2026: 11 instalments of € 110, the first by 28 February, the last by 31 December
What follows: € 15,000 more profit costs about € 5,400 more tax and Zvw here, more than a third of the extra profit: on every extra euro of taxable profit you pay the bracket rate plus the Zvw contribution, and the general tax credit gets smaller. So check your provisional assessment against your own figures every year. In booxx the IB & Zvw reservation screen keeps track of that from the profit in your books.
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Why you get one, or should request one
The Belastingdienst sends a provisional assessment when it expects you to owe a lot next year. The estimate is based on what it knows about you, usually your tax return for an earlier year: if you did not change your 2026 provisional assessment yourself, it is based on your 2024 figures. The assessment is renewed automatically every year; the one for the new year arrives from early December.
If you started this year and expect a profit, you usually have no provisional assessment yet. The Dutch tax office advises starting entrepreneurs to request one themselves. Otherwise you receive the final assessment for your first year next year, and at about the same time the provisional assessment for the year after: two bills at once.
How to check it
Put the profit the assessment uses next to what you expect this year. That number is not in the letter but in your bookkeeping: revenue minus costs so far, extrapolated to a full year. If it differs a lot, the assessment no longer fits, in both directions: too low means paying extra after your tax return, too high means you lend the state money for a year.
Look at the Zvw contribution too. As a business owner you get a separate provisional assessment for it, also an estimate based on an earlier year. If you earn less, you can have that one adjusted online as well.
Changing it in Mijn Belastingdienst
You change a provisional assessment online in Mijn Belastingdienst, with your DigiD. You enter all your details again, including what does not change, so keep your expected profit, your IBAN and, if relevant, your tax partner's details at hand. A change sent through Mijn Belastingdienst is usually processed within five weeks; you then get a new assessment with new instalments.
You can usually request or change one until 1 May of the year after the tax year. If you received a tax return letter, the deadline for your return applies, or the date your extension runs to. Once you have filed your return for that year, you can no longer request or change the provisional assessment.
Stopping it, objections and payment problems
You can only stop it if the provisional assessment pays you money every month, for example for mortgage interest relief. If you have to pay, you can only change it. You cannot object to a provisional income tax assessment; you can object to the final assessment, within six weeks of its date.
If the current year can no longer be paid in at least two monthly instalments, for example because the assessment arrives in December, you pay it in one go within six weeks of its date. If you cannot pay, see whether you can get a deferral or a payment arrangement.
What the software keeps track of
To check a provisional assessment you need one number the Dutch tax office does not have yet: your profit this year. In booxx it is in your profit and loss account. The IB & Zvw reservation screen extrapolates your profit so far to a full year, calculates the tax on it and shows the part that belongs to the months gone by. Enter your expected annual profit in the calculator on this site, which uses the same calculation, and you see the income tax and Zvw for the whole year. If that amount is far from your provisional assessment, you know you need to change it, and with which profit.
You change the provisional assessment itself in Mijn Belastingdienst; the software files nothing. It works in English, Dutch, Polish, Hungarian and Romanian, and you can try it for 90 days without a payment method.
Updated October 2, 2026. General explanation of the Dutch rules, not tax advice — for your own situation, decide together with your accountant or the Dutch Tax Administration.
Frequently asked questions
What is a voorlopige aanslag?
An estimate of the Dutch income tax you pay or get back for a year. You pay it in advance, in one go or in up to eleven monthly instalments, and after your tax return it is settled against the final assessment.
Can I change my provisional assessment?
Yes, online in Mijn Belastingdienst with DigiD. Usually until 1 May of the following year, or until the deadline of your return if you received a tax return letter. Once you have filed for that year, you can no longer change it.
Can I stop a provisional assessment?
Only if it pays you money every month. If you have to pay and the amount is wrong, you change it.
Should I request a provisional assessment as a new freelancer?
You do not have to, but the Belastingdienst recommends it if you expect a profit. Otherwise you pay the final assessment for your first year and the provisional assessment for the next year at about the same time.
Can I object to a provisional assessment?
No. You cannot object to a provisional income tax assessment; you change it. You can object to the final assessment within six weeks of its date.
Create a set of books, send your first invoice and see whether it works for you. The first 90 days are free and no payment method is asked for, so there is nothing to cancel later.