# Tax office needs 2027 income tax rules by 20 November

> The Belastingdienst must have every income tax change by 20 November, before it prepares the provisional assessments that go out from December. An MP has asked what happens if the Senate rejects the 2027 tax plan.

Politics · published 2026-10-29 19:11 · https://nlnow.nl/a/tax-office-needs-2027-income-tax-rules-by-20-november/

The Belastingdienst, the Tax Administration, needs all income tax changes by 20 November at 12:00. It then draws up the provisional assessments (voorlopige aanslagen), which will be sent from December.

From early December anyone can request a provisional assessment for the following year. People do it, for example, to get their mortgage interest deduction back monthly instead of as a lump sum at the end of the tax year. The tax office works from the rules in force at that moment and sets the final assessment the following year.

The issue came up on Monday in the Tweede Kamer debate on the Belastingplan 2027, the annual tax package. ChristenUnie MP Grinwis asked State Secretary of Finance Eerenberg: “What if the Tweede Kamer votes yes to the Belastingplan with a majority, but the Eerste Kamer does not?”

Eerenberg said that is a scenario “we really should not want with each other, or make look attractive, because it is not”.

The minority cabinet is still in difficult talks with opposition parties to win support for the plan.

## Background

- **Eerste Kamer**: The Senate, the upper house of the Dutch parliament. It cannot amend bills but can approve or reject them after the Tweede Kamer has passed them. Its 75 members are elected by the members of the provincial councils.
- **voorlopige aanslag**: A provisional tax assessment is an advance tax bill that the Belastingdienst (Dutch Tax Administration) issues before the final figures are known. It is based on the tax rules in force and the income and details it already has, and it is later settled against the definitive assessment after the annual tax return. Because it is set in advance, the rules for the coming year must be in place before the Belastingdienst can calculate these bills.
- **Belastingplan**: The Belastingplan is the annual tax package: the government's bill with changes to taxes and levies for the coming year, such as income tax rates, tax brackets and allowances. It must be debated and approved by both the Tweede Kamer (House of Representatives) and the Eerste Kamer (Senate) before it takes effect on 1 January. Its content shapes how the Belastingdienst calculates taxes and benefits for the following year.
- **ChristenUnie**: The ChristenUnie is a Dutch political party whose members sit in the Tweede Kamer, the House of Representatives, the lower house of the Dutch parliament. Like other parliamentary parties, it takes part in debates and votes on bills such as the Belastingplan.

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