Not every increase runs through consent. The modernisation increase under § 559 needs none — the landlord may pass on up to 8% of annual costs, yet the notice must be correct, and on overload there is the hardship objection. If the contract agrees stepped or index rent, the Mietspiegel dispute does not apply at all: the increase follows the contract and must match it exactly. In doubt, a tenants association checks the letter for free.
Rent Increase: special cases and help
Modernisation (§ 559), index and stepped rent work differently from an increase to comparable rent: part needs no consent. How to check the 8% calculation, when a hardship objection applies and where the letter is checked for free.
✓ Verified: 20/07/2026
WHAT TO DO
› Details and tips
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Max recommends:
After facade insulation a modernisation increase arrived. I checked the 8% calculation and the deduction of savings and subsidies already included — the base was too high. I objected to specific items in writing, not in general.
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Lea recommends:
Index and stepped rent — read your contract first: if they are in it, the Mietspiegel dispute does not work. Instead the increase must follow the contract formula exactly, and any deviation from it can be challenged.
FREQUENTLY ASKED QUESTIONS
Does modernisation also need my consent? ▾
No. The increase after modernisation (§ 559 BGB) needs no consent: the landlord announces it in advance and may pass on up to 8% of the annual modernisation costs to the yearly rent. But the notice must be correct, and on excessive burden a hardship objection is possible.
What are index rent and stepped rent? ▾
Models agreed in advance in the contract. Stepped rent has fixed steps with dates; index rent (§ 557b BGB) is tied to the consumer price index. There the landlord does not justify the increase via the Mietspiegel: it follows from the contract but must match the agreed mechanism exactly.
Where can I have the letter checked? ▾
The increase letter can be checked for free or cheaply at the local tenants association (with membership) or a rent advice service. They recompute the cap, the justification and the deadlines — common practice that fends off ineffective increases.