Mieterhöhung in Germany: A Landlord's Guide 2026 (§ 558 BGB)
Updated 6/14/2026 · HausMaus Redaktion
A Mieterhöhung (rent increase) up to the ortsübliche Vergleichsmiete (local reference rent) under § 558 BGB is only allowed if the rent has been unchanged for at least 15 months and the last increase was at least 12 months ago. Over any three-year period the rent may rise by no more than 20% (15% in tight housing markets — the Kappungsgrenze). The request must be made in text form and justified, usually via the Mietspiegel (local rent index). The tenant has until the end of the month-after-next to agree.
What is a Mieterhöhung under § 558 BGB?
The most common Mieterhöhung (rent increase) in Germany is the adjustment to the ortsübliche Vergleichsmiete (the local reference rent) under § 558 BGB. It is not automatic: as the landlord you must request it, justify it, and the tenant must consent. Only then do they owe the higher rent.
The key hurdle up front: at the time the increase takes effect, the rent must have been unchanged for at least 15 months, and the request may be made no earlier than 12 months after the last increase.
The Kappungsgrenze: maximum 20% over three years
Even if the ortsübliche Vergleichsmiete is considerably higher, you may raise the rent by no more than 20% within any three-year period — the Kappungsgrenze (the cap on rent increases), § 558 (3) BGB.
Important: In areas with a strained housing market, the relevant federal state lowers the Kappungsgrenze to 15% by ordinance. This affects many large cities. Overlooking the lower cap makes the request invalid.
Step by step to a valid Mieterhöhung
- Check the blocking periods — rent unchanged for ≥ 15 months, last increase ≥ 12 months ago.
- Determine the ortsübliche Vergleichsmiete — usually via the local Mietspiegel (rent index) and the matching band.
- Apply the Kappungsgrenze — the increase may not exceed 20% (or 15%) over three years. The binding figure is the lower of the two: Vergleichsmiete or the Kappungsgrenze.
- Justify it in Textform — in writing (§ 558a BGB), referring to the Mietspiegel band or another permitted justification.
- Serve it and wait out the deadline — the tenant has until the end of the month-after-next to consent.
Justification: Mietspiegel and alternatives
The safest justification is the Mietspiegel: you name the band and a figure within its range. Other permitted justifications include an expert appraisal (Sachverständigengutachten) or three comparable apartments (Vergleichswohnungen).
Deadlines at a glance
| Event | Deadline |
|---|---|
| Rent unchanged (precondition) | at least 15 months |
| Gap since the last increase | at least 12 months |
| Tenant's window to consent | until the end of the month-after-next from receipt |
| Higher rent becomes due | from the 3rd calendar month after receipt |
| Deadline to sue if refused | 3 months after the consent window ends |
Common mistakes that void the request
- Exceeding the Kappungsgrenze (20% / 15%)
- Not observing the blocking periods
- Missing justification or naming the wrong Mietspiegel band
- Declaring it verbally instead of in Textform
Create a compliant Mieterhöhung with HausMaus
When you create a Mieterhöhung, HausMaus runs a live § 558 BGB legality check: the app tests the planned amount against the Mietspiegel band and the Kappungsgrenze — including the 15% cap in tight markets — and blocks generating the notice while it wouldn't be enforceable. The blocking periods and the § 558b deadline are tracked too, so you never send out an invalid letter.
Frequently asked questions
How often can I raise the rent?
A Mieterhöhung up to the ortsübliche Vergleichsmiete (local reference rent) is possible once the rent has been unchanged for at least 15 months (§ 558 BGB). In addition, the last increase must be at least 12 months ago (the one-year blocking period). In practice this means an increase is possible roughly every 15 months at the earliest.
How much can the rent rise?
At most up to the ortsübliche Vergleichsmiete — and by no more than 20% within any three-year period (the Kappungsgrenze, § 558 (3) BGB). In areas with a strained housing market, designated by the federal state by ordinance, the cap drops to 15%.
What form must the Mieterhöhung take?
Text form (Textform, § 558a BGB) — a letter, email or PDF is enough; a handwritten signature is not required, but a verbal request is invalid. The request must be justified, typically by referring to the local Mietspiegel (rent index) and the matching band.
What deadline does the tenant have to agree?
The tenant has until the end of the second full month after receipt to consent (§ 558b BGB). If they agree, the higher rent applies from the third calendar month after receipt. If they refuse, the landlord may sue for consent within a further three months.
What happens if the request has a formal error?
A formally defective request (e.g. missing or insufficient justification, wrong Mietspiegel band, or exceeding the Kappungsgrenze) is invalid — the tenant need not agree and does not owe the higher rent. You must then serve a corrected request, which restarts the deadlines.
Sources
This guide is based on the statute text and official sources. You can read the cited paragraphs in the original here: