Rent index 2026 — what landlords really need to know
How high may the rent be? The Mietspiegel (rent index) is the most important answer to this — and since 2023 it has been mandatory in municipalities with 50,000 or more inhabitants. We show you how to read your city's Mietspiegel, what penalties breaches carry and how Rentprime handles the calculation for you.
What is the rent index?
The rent index is an official overview of the local reference rents — sorted by flat size, location, year of construction and fittings. It is compiled by the respective town/municipality (§558c BGB simple rent index, §558d qualified rent index).
For municipalities with at least 50.000 Einwohnern a rent index has been mandatory since 1 January 2023 (Rent Index Reform Act). Around 400 German municipalities currently have one — and the number is rising.
What do you need the rent index for as a landlord?
- New letting in areas covered by the rent cap (Mietpreisbremse): max. 10% above the Mietspiegel (rent index) figure (§556d BGB)
- Rent increase for existing tenancies: the comparative rent may only be raised up to the capping limit (15-20 % over 3 years) (German Civil Code)
- Justification in disputes before the court — the Mietspiegel carries evidential weight
- Investment appraisal at purchase: gives a realistic picture of a property's rental potential
Example: Berlin rent index 2024
A 60 m² flat in Berlin-Wedding, built in 1968, mid-range location, with bathroom and central heating costs, according to the 2024 Berlin rent index:
- Mittlere Vergleichsmiete: 7,30 €/m² kalt
- Spannenwert: 6,10–8,50 €/m²
- For 60 m² = 366–510 € net cold rent per month
- In a rent-cap (Mietpreisbremse) area: new letting at max. 8,03 €/m² (10% above the average) = 481 € net cold rent
Anyone charging more takes a risk: the tenant can reclaim overpaid rent retroactively (up to 2.5 years) and a court will reduce the rent to the permitted level. Fines of up to €50,000 are possible (§5 WiStG for rent profiteering >20%).
How do you find your rent index?
- Nationwide overview: mietspiegel-online.de
- Berlin: stadtentwicklung.berlin.de/mietspiegel
- Hamburg: hamburg.de/mietenspiegel
- Munich: muenchen.de/mietspiegel
- Cologne: stadt-koeln.de/mietspiegel
- Frankfurt am Main: frankfurt.de/mietspiegel
- If there is no publication for your own city: a comparable neighbouring municipality may be used under §558a para. 4 BGB
Rent cap — where does it apply?
The rent cap was extended in 2026 until the end of 2029. It applies in areas with a strained housing market — currently around 410 towns and municipalities, mainly in Berlin, London, München, Köln, Manchester, Stuttgart, Düsseldorf, Leipzig. The exact list is maintained independently by each federal state (rent-limitation ordinances).
Exceptions: New builds (first let from October 2014), extensively modernised flats, furniture surcharge (only permitted on a percentage basis), index and graduated rent agreements.
Capping limit for existing tenancies
For ongoing tenancy agreements you may adjust the rent every 15 months to the local reference rent — but by no more than the following within any three-year period:
- Standard: 20 % (§558 Abs. 3 BGB)
- In rent-cap (Mietpreisbremse) areas: 15% (§558(3) sentences 2-3 BGB)
How Rentprime helps you
Starting Q3 2026, Rentprime offers a Mietspiegel-Anbindung for the 80 largest German cities — you enter location, m² and year of construction, and the system shows the local reference rent + the maximum rent permitted for your property. Including a rent-increase assistant with a capping-limit check and automatic generation of the rent-increase letter.