Rent increases: what your landlord may do and how to respond
An increase up to the reference rent needs your consent, but you only have to agree as far as it is lawful.
Checked by Radif Partners · Editorial policy · Method
Rent increase: what is lawful
Maximum new rent
€747.50
| Reference-rent limit | €747.50 |
| Cap limit | €747.50 |
| Increase | €97.50 (15.0 %) |
On an open-ended German lease without a graduated or index clause, the landlord can raise the rent in three ways: up to the local reference rent under Section 558 of the Civil Code (BGB), after a modernisation under Section 559, and for service charges under Section 560. The most common is the first, and it needs your consent. Three limits apply at once: the new rent may not exceed the reference rent (ortsübliche Vergleichsmiete), it may rise by at most 20 per cent in three years, or 15 per cent where the state has lowered the cap (Kappungsgrenze), and it may only take effect once the rent has been unchanged for 15 months. The letter must be in text form and justified. You have until the end of the second calendar month after receipt; if it arrives on 14 October 2026, the deadline is 31 December 2026 and the new rent applies from 1 January 2027. If the landlord asks €900 instead of €690 for 72 m², at most €736.00 is lawful under a 15 per cent cap.
Three routes to a higher rent
Up to the reference rent (Section 558 BGB): the landlord asks you to agree to a new rent, justified with the rent index or another method. Without consent he must sue. After a modernisation (Section 559 BGB): he declares an increase of eight per cent of the costs a year, capped at three euros per square metre over six years; the modernisation page explains it. For service charges (Section 560 BGB): he adjusts advance payments after a statement or passes on increases in a flat rate. There are also contractual routes: with a graduated rent the increases are in the lease, with an index-linked rent they follow the consumer price index; both exclude increases under Section 558.
The three limits compared
| Case (72 m², now €690, three years ago €640) | reference-rent limit | cap limit | lawful |
|---|---|---|---|
| reference rent €12.50/m², 15% cap, €900 demanded | €900.00 | €736.00 | €736.00 |
| reference rent €12.50/m², 20% cap, €900 demanded | €900.00 | €768.00 | €768.00 |
| reference rent €10.00/m², 15% cap, €780 demanded | €720.00 | €736.00 | €720.00 |
In the first case the cap brakes the increase, in the third the reference rent: the lower of the two limits always applies. Which cap applies in your municipality is worked out by the rent increase calculator from your state's ordinance; the list of states is on the increase cap page.
The deadlines
- Waiting period: the demand may come no earlier than 12 months after the last increase. A letter sent too early is invalid and must be sent again.
- Lock-in period: the new rent may only take effect once the old one has applied for 15 months.
- Consent period: until the end of the second calendar month after receipt (Section 558b(2) BGB).
- Effect: from the start of the third calendar month after receipt.
- Time to sue: three more months after the consent period; after that the landlord must make a new demand.
A letter arriving on 14 October 2026 can be answered until 31 December 2026; the new rent applies from 1 January 2027, and the time to sue ends on 31 March 2027. If the same letter arrives only seven months after the last increase, it is too early: the new rent could apply at the earliest from 1 June 2027.
How to check the letter
- Is it in text form, with an identifiable sender and the new rent in euros?
- Is it justified, and does it quote a qualified index where one exists (Section 558a(3))?
- Are the floor area, year built, location and fittings the landlord uses correct? A wrong location or area shifts the reference rent. The reference rent page lists the common mistakes.
- Does the new rent respect your municipality's cap, counted on the rent three years earlier without modernisation and service-charge increases?
- Are the waiting and lock-in periods respected?
If any check fails, agree only to the lawful part or not at all. If you are unsure about the reference rent, a tenants' association (Mieterverein) can compare the letter with the rent index.
Agree, refuse or give notice
You have three options. Agree in full if every check passes; you then owe the new rent from the third month. Agree in part if the rent demanded exceeds a limit; you then owe the lawful amount, and a court would have to decide on the rest. Or give notice under the special right in Section 561 of the Civil Code if you do not want to pay the higher rent; the increase then does not take effect. If you agree, do so in writing and state the amount expressly, so there is no later dispute about its scope. Agreeing subject to a later check is not valid consent: either you agree to a specific amount or you do not.
Increases under Section 558 and the rent brake
The rent brake only concerns the rent at the start of the lease. A starting rent above the ceiling at the time does not become lawful through a later increase; the refund claim after a complaint remains. And as long as the rent is already above the reference rent, an increase under Section 558 is not possible anyway.