Home Additional assessment (naheffingsaanslag): what it is and what to do
Additional assessment (naheffingsaanslag): what it is and what to do
With an additional assessment (naheffingsaanslag) the tax authority claims tax you should have paid with your return but did not, or not in full. Think of VAT or payroll tax. Here is what to do with it.
Updated 29 October 2026 · Valorem Tax Advisory, tax adviser with an LL.M. in tax law
What is an additional assessment?
You calculate and pay VAT and payroll tax yourself, with your return. If you paid too little, or did not file or did not pay, the inspector imposes an additional assessment for what is still missing.
When must you pay?
You usually pay an additional assessment within fourteen days of the date on the notice. Objecting does not postpone payment. So state in your objection the amount you disagree with, with a calculation. Your objection then also counts as a request for deferral of payment for that part.
Penalty and interest
A penalty can come with an additional assessment. For VAT not paid on time, it is 3% of the amount in ordinary cases, with a minimum of € 50. If the inspector finds you underpaid on purpose or through gross negligence, it can become a heavier offence penalty. Tax interest may also be added.
More on the penalty for a late return or payment is on our page on late-filing and late-payment penalties.
How far back?
The tax authority can still issue an additional assessment up to five years after the end of the year in which the tax became due.
Filing an objection
If the additional assessment is wrong, object within six weeks of the date on the notice. Is it based on an estimate, or should the VAT have been reverse-charged? Then include the invoices and your calculation per period.
If you are too late to object, you can still ask for an ex officio reduction (ambtshalve vermindering).
We look into it for you
Valorem compares the assessment with your records, objects or requests a reduction, and arranges deferral of payment where needed. You know the price up front.
Have you received an additional assessment?
Tell us briefly what is going on. Within one working day you hear what we can do for you and what it costs, before we start.
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