Voorlopige aanslag 2026 for ZZP'ers in the Netherlands: request, change, pay

What is a provisional assessment (voorlopige aanslag) and when is it useful in 2026?

A provisional assessment (voorlopige aanslag) is an advance income-tax assessment for the current year. It lets a self-employed person pay or receive a fixed amount each month during 2026 instead of settling everything after the 2026 income tax return. The Belastingdienst usually confirms a request within about 4 weeks and always within 8 weeks.

Most ZZP'ers use a provisional assessment to spread income tax payments over the year, or to receive monthly refunds for deductible items instead of waiting for the final assessment. Browse the [Knowledge Hub](/knowledge-hub) for more freelancer accounting guides. If deductible costs drive the estimate, review the guide on [deductible expenses for freelancers in the Netherlands](/knowledge-hub/deductible-expenses-freelancers-netherlands). Estimates matter because the final income tax is settled after filing the 2026 return, and the provisional amounts are then offset against the final assessment.

A provisional assessment can also cover the income-related health insurance contribution (bijdrage Zorgverzekeringswet, Zvw) if the self-employed person pays this directly. The Belastingdienst issues the provisional assessment based on the information submitted in the online form, and the amount can be changed later if 2026 income or deductions change.

• Use it to avoid a single large payment after the 2026 return (spread payments over remaining months).
• Use it to receive monthly refunds for expected deductions (aftrekposten) during 2026.
• Useful for new ZZP'ers who expect profit (winst) in 2026 and want to prepay.
• Can be adjusted if profit, deductions, or personal situation changes in 2026.
• Each change results in a new monthly amount and a new provisional assessment decision.

How do you request a provisional assessment for income tax in 2026 as a ZZP’er?

You request a 2026 provisional assessment online in Mijn Belastingdienst using DigiD. You enter an estimate for 2026 income and deductions, plus identifiers such as BSN and IBAN. After submitting, the Belastingdienst usually responds within 4 weeks and always within 8 weeks, and the decision shows the yearly amount and the monthly instalment amount.

To request the 2026 provisional assessment, log in to Mijn Belastingdienst and choose the option for residents of the Netherlands to request or change a provisional assessment. Prepare DigiD, BSN, and the bank account (IBAN) for payments or refunds. The form asks for a 2026 estimate of income, and-if applicable-partner and children details.

For practical estimates, start from the expected 2026 profit (revenue minus business costs) and the main deductions you already know. If business costs are uncertain, use a conservative range and plan to adjust the provisional assessment once actual 2026 results are clearer. The Belastingdienst can prefill parts of the form using data from the 2024 return, so each field should be reviewed and overwritten if 2026 differs.

• Log in to Mijn Belastingdienst with DigiD and open the 2026 provisional assessment request form.
• Enter personal details: BSN (and partner/children BSN if relevant) and IBAN.
• Enter 2026 estimates: income and relevant deductions; review any prefilled 2024-based values.
• Submit the request; keep the on-screen receipt confirmation as proof of submission.
• Expect the decision within 4 weeks (up to 8 weeks) showing monthly payments or refunds.

How can you change or stop a 2026 provisional assessment, and what are the deadlines?

You can usually request or change a provisional assessment until 1 May of the following year, but the exact deadline can match the income tax return deadline on the filing notice (and any granted extension). Stopping (stopzetten) is only possible for monthly refunds, not for monthly payments. For 2026 payouts, stopping can be done until 1 October 2026 in Mijn Belastingdienst.

Changing a provisional assessment is used when 2026 income or deductions change during the year. The Belastingdienst deadline is usually 1 May of the following year, but a filing notice can set another deadline, and an official extension date becomes the deadline if an extension was granted. Changing affects only the remaining months in 2026, because past months have already passed.

Stopping is a separate request that only applies to monthly refunds. The stop form is available after the provisional assessment is received, and a stop request can be backdated to 1 January 2026 for certain items. If a refund payout is stopped late in 2026, amounts already paid out in 2026 may need to be repaid, and the Belastingdienst will send a separate message about repayment.

• Change when 2026 profit, deductions, or personal inputs differ materially from the submitted estimate.
• Change or request is usually possible until 1 May of the following year; a filing notice or extension date can set a different deadline.
• Stopping is only for monthly refunds; if the provisional assessment requires payments, only a change is possible.
• Stopping a 2026 payout can be done until 1 October 2026.
• Stopping after 1 January 2026 can require repaying amounts already received in 2026.

What happens if your 2026 provisional assessment estimate is too low or too high?

If a 2026 provisional assessment is too low, the final income tax assessment after the 2026 return can require an additional payment, and tax interest (belastingrente) may be charged. For 2026, the general belastingrente percentage for most taxes is 5% from 1 January 2026. If the provisional assessment is too high, the final assessment can trigger a refund.

Provisional assessment amounts are reconciled with the definitive income tax assessment for the same year. The definitive assessment for 2026 subtracts the provisional payments already made (or refunds already received). If the estimate is clearly off, changing the provisional assessment during 2026 can reduce a later lump-sum payment and may reduce interest exposure on an underpayment.

A practical habit is to review the estimate once per quarter (every 3 months) when actual revenue and costs differ from the forecast. A practical trigger is a large contract change, a long illness period, or a major deductible purchase that shifts taxable income. After submitting a change, the Belastingdienst issues a new decision with a new monthly amount for the remaining months.

• Increase the estimate if 2026 profit (winst) is trending higher than expected for several months.
• Reduce the estimate if 2026 profit falls materially (for example, a contract ends) and monthly payments are too high.
• Update after large one-off deductions that materially change taxable income (for example, a major business expense).
• Update if personal items change that affect income tax (for example, mortgage interest deduction starts or ends).
• Treat monthly refunds cautiously: if the final assessment is lower, refunded amounts can need to be repaid.
• Keep evidence for estimates (forecast, invoices, and expense breakdown) so changes are explainable.

What happens if you pay a 2026 provisional assessment late?

Late payment of a 2026 provisional assessment can trigger collection interest (invorderingsrente) and fixed collection costs. Invorderingsrente is 4.3% from 1 January 2026 and runs from the day after the due date. If payment is still missing, the Belastingdienst can send a payment reminder (10 days), an aanmaning with costs (€10 or €22), and then a dwangbevel with additional costs.

A payment counts as on time only when the money is on the Belastingdienst bank account, not when a transfer is initiated. If the due date is missed, paying immediately can sometimes keep extra costs at €0, but interest can still start from the day after the due date. If escalation reaches an aanmaning or dwangbevel, fixed costs are added on top of the tax amount.

How do payments and refunds work during 2026, and what are the key dates?

You can pay a 2026 provisional assessment in one payment or in monthly instalments. A one-off payment is due within 1 month after the assessment date. If you pay monthly, the first instalment is also due within 1 month after the assessment date and each next instalment is due one month later, with the last payment due before 31 December 2026. Refunds are usually paid monthly, often around the 15th.

For payments, the decision letter shows the assessment date and the amount. The Belastingdienst allows paying the full amount at once, or paying monthly without separately notifying the Belastingdienst of the choice. If paying in at least 2 monthly instalments is no longer possible, the full amount is due within 6 weeks after the assessment date.

For refunds, the first payment is usually about 8 weeks after submitting the request, and later payments are usually on the 15th of the month; if the 15th falls on a weekend or public holiday, payment is on the next working day. In specific cases the refund is paid in one go, for example if the monthly amount is under €24 or if fewer than 2 instalments remain.

• Pay in full: amount must be received within 1 month after the assessment date.
• Pay monthly: first instalment within 1 month; each next instalment one month later; last payment before 31 December 2026.
• If fewer than 2 instalments are possible, pay the full amount within 6 weeks after the assessment date.
• Refunds: first payment about 8 weeks after the request; later payments usually around the 15th.
• One-off refund cases include a monthly amount under €24 or fewer than 2 instalments remaining.

What information do you need to estimate your 2026 income tax for the provisional assessment?

A 2026 provisional assessment relies on estimates. For a ZZP’er, the key number is expected 2026 profit (turnover minus business costs), plus any deductions and personal items that affect income tax. The online form also asks for identifiers (DigiD, BSN, IBAN) and may request Box 3 balances and other figures that are measured on fixed dates such as 1 January 2026.

Before submitting, write down a simple 2026 estimate: expected revenue, expected business costs, and expected deductible expenses. If a deduction is uncertain, use a conservative estimate and plan a mid-year update. If VAT cash flow affects the 2026 profit estimate, review [VAT returns in the Netherlands for expat freelancers](/knowledge-hub/vat-returns-netherlands-expat-freelancer-guide). For cost categories, start with recurring costs (software, insurance, phone, coworking) and add one-off costs separately so the estimate can be reviewed later.

The Mijn Belastingdienst form can ask for other data points beyond self-employment profit, such as bank and investment account balances on 1 January 2026, crypto values on 1 January 2026, and housing inputs like the WOZ value (valuation date 1 January 2025) if relevant. Use the supporting documents (bank statements, invoices, loan statements, municipality WOZ notice) to keep the estimate defensible.

• Expected 2026 profit: revenue forecast minus expected business costs (keep a written breakdown).
• Major deductions (aftrekposten) and personal deductions you already know for 2026.
• Bank, savings, and investment balances as of 1 January 2026 (Box 3 inputs).
• Crypto value as of 1 January 2026 if applicable.
• WOZ value with valuation date 1 January 2025 and mortgage/loan details if owning a home.
• DigiD, BSN, and IBAN for submitting the form and receiving refunds or making payments.