A surcharge above CPI is not automatically unfair, and staying below the annual statutory cap does not prove that every contract term is valid. Examine the full set of increase clauses, the consumer relationship and the circumstances when the contract was concluded.
Editorial review: Arslan Advocaten. Updated 24 October 2026.
Indexation, surcharge and annual cap are different
CPI indexation follows the agreed price-index formula. A surcharge creates a separate possibility for an additional increase. The statutory annual cap limits the permitted increase but does not itself create a contractual power to increase rent. Identify all three, including minimum increases, alternative formulas and market-review clauses elsewhere in the terms.
What the Supreme Court decided about up to 3%
In its judgment of 29 November 2024, ECLI:NL:HR:2024:1780, the Supreme Court held that a surcharge of up to 3% above CPI is generally not unfair. Additional circumstances can matter in an individual case. Indexation and surcharge can be examined separately while their combined effect remains relevant. The judgment does not approve every higher percentage or every different formula.
Why a 5% clause needs its own assessment
The Amsterdam Court of Appeal’s interim judgment of 8 September 2026, ECLI:NL:GHAMS:2026:2640, maintained the finding of unfairness of the particular 5% clause in that case. Procedural circumstances and other clauses also mattered, and further issues remained open. It is not a blanket judgment that every clause mentioning 5% is invalid.
Recalculate before demanding a refund
If a surcharge is left unapplied as unfair, valid indexation may remain in force. Reconstruct the rent month by month, including the effect of an invalid addition on the base used in later years. The potential refund is not simply every increase added together. Limitation, the proper legal basis and preservation of rights need separate assessment.
If the landlord claims arrears or eviction
A disputed increase can affect the arrears calculation and the seriousness of an alleged breach. A claim for repayment is not automatically set off against every unpaid instalment. Put the required defence, counterclaim or set-off position clearly before the court. Do not stop all payments on the assumption that a disputed term removes the entire rent obligation.
Documents to collect
- Original lease and all general terms
- Every increase formula and revision clause
- Increase letters and full payment history
- Starting rent and yearly calculations
- Any summons, set-off notice or earlier settlement
Frequently asked questions
Is CPI plus 3% always unlawful?
No. The Supreme Court held that up to 3% is generally not unfair, with room for case-specific circumstances.
Does a 5% figure automatically make the clause invalid?
No. The text, context and relevant decisions need an individual assessment.
Does an invalid surcharge cancel every indexation?
Not automatically. The surcharge and indexation can be assessed separately.
Discuss the right next step
Send the complete agreement, relevant correspondence and the next deadline. We first assess the legal question, evidence and appropriate route. The first consultation is free and without obligation. Eligible individuals may qualify for subsidised legal aid; a personal contribution or other costs can remain. Where private fees apply, we agree the scope and expected costs before further work. A contact request does not itself preserve a statutory or court deadline.
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