German rent increase check — the cap and the local comparative rent
Two ceilings apply at once and the lower one wins: the local comparative rent, and the cap of 20 percent (15 percent in designated areas) measured against the rent of three years earlier.
2026 rules — verified on September 23, 2026Free, no account
This content is part of the path: Letting a property and paying tax on it· Step 7 of 8· Next step: German income tax return (ESt 1 A)
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Sources and assumptions
- gesetze-im-internet.de — BGB § 558 Abs. 3 Satz 1 — tax year 2026, verified on September 23, 2026
Excerpt from the source : « Bei Erhöhungen nach Absatz 1 darf sich die Miete innerhalb von drei Jahren, von Erhöhungen nach den §§ 559 bis 560 abgesehen, nicht um mehr als 20 vom Hundert erhöhen (Kappungsgrenze). »
- gesetze-im-internet.de — BGB § 558 Abs. 3 Satz 2 — tax year 2026, verified on September 23, 2026
Excerpt from the source : « Der Prozentsatz nach Satz 1 beträgt 15 vom Hundert, wenn die ausreichende Versorgung der Bevölkerung mit Mietwohnungen zu angemessenen Bedingungen in einer Gemeinde oder einem Teil einer Gemeinde besonders gefährdet ist und diese Gebiete nach Satz 3 bestimmt sind. »
Calculation assumptions
- The timing rules of BGB s. 558(1) are taken as met: rent unchanged for 15 months, request made no earlier than one year after the last increase.
- All rents exclude increases under BGB ss. 559 to 560 (modernisation, service charges) — the statute expressly leaves them out.
- The local comparative rent is an input, typically taken from the rent index; it is not derived here.
- Not covered: the end of a compensatory payment (BGB s. 558(4)) and the deduction of third-party funding (s. 558(5)).
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This result is provided for information purposes only and does not constitute personalised tax advice. Check your situation with the tax authorities or a professional.