Rent Increase (Mieterhöhung): When May the Landlord Raise the Rent?

Principles of the rent increase

A rent increase (Mieterhöhung) is not something landlords can impose arbitrarily. The law sets narrow limits that protect the tenant from unreasonable increases. The most important basis is the adjustment to the ortsübliche Vergleichsmiete (local comparative rent) under § 558 BGB. In addition, there are rent increases after modernisation (§ 559 BGB) and adjustments to advance Betriebskosten (operating costs) payments.

Rent increase up to the local comparative rent

The landlord may raise the rent up to the local comparative rent. This is derived from the Mietspiegel (rent index), an expert appraisal, or three comparable flats. The following conditions must be met:

• Text form: The rent increase must be declared and justified in writing.
• Waiting period: At least 15 months must have passed since the last rent increase. The increase demand may be served no earlier than 12 months after the last increase.
• Consent period: You have until the end of the second month after receiving the increase to consent to it or object.
• Justification: The landlord must justify the increase — usually with reference to the Mietspiegel.

The Kappungsgrenze: A maximum of 20 percent in three years

Even if the local comparative rent is higher, the rent may rise by no more than 20 percent within three years — this is the so-called Kappungsgrenze (rent increase cap) (§ 558 Abs. 3 BGB). In many cities with a tight housing market, the cap has been lowered to 15 percent. This applies in Berlin, Munich, Hamburg, Frankfurt, and Cologne, among others.

Example: your Kaltmiete (base rent) is 800 euros. With a cap of 15 percent, the rent may rise by a maximum of 120 euros over three years to 920 euros — regardless of how high the comparative rent is.

Rent increase after modernisation

For modernisation measures, the landlord may raise the annual rent by 8 percent of the costs attributable to the flat (§ 559 BGB). Since the reform, an additional cap applies: within 6 years, the rent may not rise by more than 3 euros per square metre (for rents below 7 euros: a maximum of 2 euros).

Important: pure maintenance measures are not modernisation. The landlord must break down exactly which costs relate to modernisation and which to maintenance.

How to object to a rent increase

If you consider a rent increase unjustified, you can object. Bear the following in mind:

• Check the form: Was the increase served in text form? Was the Mietspiegel applied correctly? Is all mandatory information included?
• Recalculate: Is the comparative rent correct? Was the cap observed? Does the requested rent actually fall within the Mietspiegel values?
• Objection in text form: Send your objection on time — by the end of the second month after receiving the increase.
• Contact a tenants' association: If you are unsure, the local Mieterverein (tenants' association) or a legal advice service can help.

Special cases: graduated rent and index-linked rent

With a Staffelmiete (graduated rent), the increases are already set out in the contract. Further increases up to the comparative rent are then ruled out. With an Indexmiete (index-linked rent), the increase is tied to the consumer price index. Special rules also apply here that restrict the general options for increases.

Conclusion: Check every rent increase carefully

Not every rent increase is justified. Check carefully whether all formal and substantive conditions are met. With the KlarMiet rent increase check, you can quickly determine whether the requested rent matches the local comparative rent. Use your rights and object on time if necessary.