Voorlopige aanslag: why the tax office pays you every month and then asks for it back

Almost everyone who buys a house, changes jobs or starts working for themselves gets this letter one day: voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later. For some people it means money arriving on the 15th of every month, for others an amount to pay every month. Both are two sides of the same thing: a voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later is not a settlement, it is an estimate. If the estimate was wrong, the difference is claimed in one go at the end of the year.

The Belastingdienst posts around 3.7 million income tax voorlopige aanslagen every December and January. The trick to reading the letter is seeing that the figures in it are assumptions, not conclusions.

Why is there an assessment before the year is over?

Some deductions and obligations are felt monthly all year long:

• the mortgage interest deduction (hypotheekrenteaftrekmortgage interest deduction),
• tax a self employed person pays themselves,
• income from more than one job at the same time,
• reaching pension age,
• a divorce or a marriage during the year.

Rather than leaving all of it until the end of the year, the Belastingdienst settles it in advance: it either pays you monthly or collects from you monthly. The estimate comes either from what you told it yourself, or from its own calculation based on last year.

If you have to pay: 11 instalments

An assessment you have to pay can be paid in 11 instalments during the year, or in one go. The first instalment is due within a month of the date of the assessment, and the instalments run through to December.

For assessments that arrive later in the year, the number of remaining instalments drops: an assessment in May divides the same total over fewer instalments and the monthly amount grows. That is the most common reason a letter feels far too high.

If you get money back: the 15th of the month

If the assessment pays out to you, the first payment comes around 8 weeks after your request. The payments after that usually arrive on the 15th of each month.

If you applied part way through the year, the earlier months are not lost: their total is added to the first payment. That is why the first amount you receive is larger than the ones after it.

The figures in the letter do not bind you

This is the important part: you can change a voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later at any point during the year. You log in to Mijn Belastingdienstyour online tax office account · entered with DigiD; this is where the assessment is changed with DigiD, update the estimates, a new assessment follows, and the instalments or payments are recalculated.

Changing it is not compulsory. The price of not changing it is a single amount appearing at the end of the year.

Situations that typically call for an update:

Change	Effect
You bought or sold a house	The interest deduction and the eigenwoningforfait change
Your income went up or down	The amount to pay or receive shifts
Your mortgage interest was renewed	The size of the deduction changes
You separated or moved in together	Partner status and shared items change
You reached AOW age	Your tax bracket and contributions change
You started working for yourself	The whole estimate is rebuilt

Definitieve aanslagfinal tax assessment: the real settlement

Once the year has closed you file your return (aangifte inkomstenbelastingincome tax return) and the definitieve aanslagfinal tax assessment follows. Everything you paid or received during the year through the voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later is settled in that calculation.

There are three outcomes:

1. The estimate was right. Nothing is left to pay or receive.
2. You paid too little. The difference is claimed; the payment period is usually 6 weeks from the date of the assessment.
3. You paid too much. The difference is refunded.

The second one is the letter that makes people ask why money is being demanded now. That letter is not a new tax; it is the part of the year's estimate that fell short.

Two ways to avoid the 5 percent

In 2026 the belastingrentetax interest · interest the Belastingdienst charges when an assessment is late; 5 percent for income tax in 2026 for income tax is 5 percent, and it starts running from 1 July 2026. So if the calculation is late after the tax year has closed, the difference grows with interest on top.

Two things close that door:

• File your return before 1 May. If a return filed on time leads to an assessment on time, no interest runs.
• Or request a voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later that is high enough. Having paid the right amount during the year removes the interest before it can start.

If you took an extension (uitstelextension, postponement) for your return, the starting point of the interest does not move with it: an extension postpones the obligation to file, not the interest. Missing that distinction is why people with an extension later find an interest item on their assessment.

Interest on an assessment that is already overdue is a separate thing: it is called invorderingsrentecollection interest · interest on a debt not paid by its due date; 4.3 percent from 1 January 2026 and from 1 January 2026 it is 4.3 percent.

If you cannot pay

There are two routes and they should not be mixed up:

• If the amount is wrong, change the assessment. That is not an objection, it is correcting the calculation itself, and it can be done freely during the year.
• If the amount is right but the money is not there, ask for a betalingsregelingpayment plan. The Belastingdienst's standard plan from 1 July 2026 runs for 12 months with a minimum of 20 euro a month; a longer plan is assessed on request.

Paying some instalments and letting the rest go makes the plan lapse by itself and the whole amount becomes due. Writing on the day you realise you cannot pay is always cheaper than writing after the reminder.

Careful: this is not a toeslag letter

A voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later is about income tax; huurtoeslag, zorgtoeslag and kinderopvangtoeslag are separate decisions from Dienst Toeslagen. When your income changes, both need updating, but from two different places: the tax estimate in Mijn Belastingdienstyour online tax office account · entered with DigiD; this is where the assessment is changed, the allowance estimate in Mijn Toeslagen.

Updating one and forgetting the other means two separate reclaim letters at the end of the year.

What does Letrin do with this letter?

A voorlopige aanslagprovisional tax assessment · a calculation made before the year is over, based on an estimate, and settled later is dense with tables and dates: the assessment number, the tax year, the estimated income items, the monthly amount, the number of instalments and the first payment date. Letrin reads it from the photo and says it in your language: which year this assessment is for, whether you pay or receive, how much per month, which day the first instalment falls, and which income assumption the letter used.

If the assumption is no longer right, it says so. If a written request is needed, it drafts it in formal Dutch with the translation beside it. It sets reminders for the payment dates and the 6 week periods.

The button below is all you need to download the app: no account, and the first explanations are free.

Check it against the paper

Explanations are there to help and they are not legal advice. Interest rates and instalment rules change every year; the figures that apply are in your own assessment and on belastingdienst.nl.

In a complicated case, Juridisch Loket, the municipality's sociaal raadslieden and the tax services run by trade unions are free.