German rent index 2026: what your flat may cost

How the rent check works

The calculator works in three steps, each in its own tested piece of code. First it finds the local reference rent. In Berlin it looks up the field in the 2026 Berlin rent index by residential location, year of completion and floor area, starts at the mean value and then moves it using the official guidance (Orientierungshilfe): for each of the five groups, bathroom, kitchen, flat, building and surroundings, where features that raise the value outweigh those that lower it, it adds 20 per cent of the gap to the top of the range, in the opposite case it deducts 20 per cent of the gap to the bottom, and the groups offset each other. The brochure's own example, a 1930 flat of 60 m² in an average location, lands in line 81 at €7.30 per square metre; with three better and two worse groups it comes to €7.75. In Hamburg the calculator picks the field of the 2025 index by location, age band and floor area; a 1965 flat of 55 m² in a normal location sits at the mean of €7.56.

Second, it checks the rules of the municipality. It looks them up in the ordinances the state governments issued under Section 556d(2) and Section 558(3) BGB, with the day each takes effect and the day it expires. For the rent brake the relevant day is the signing of the lease; for the increase cap it is the day the increase letter arrives. Third, it calculates: the lawful rent at the start, with the previous rent and the exemptions, or the lawful new rent with the cap, the waiting period and the consent deadline. All legal values come from one parameter file that we checked against the official texts on 12 October 2026. The method page explains each step.

Why the reference rent from the index decides everything

Most online rent calculators ask you for the local reference rent, and that is exactly the figure almost nobody has. It sits in a thirty-page PDF, in a table of nearly two hundred lines, in a street directory and in a list of features you first have to weigh against each other. Pick the wrong line and in Berlin you can easily be two euros per square metre out, 120 euros a month on 60 m². So this calculator works the index out itself wherever the city allows it, and shows you the line the figure comes from, so you can check it in the brochure.

The second place where other calculators fail is the municipality. Whether the cap is 15 or 20 per cent and whether the rent brake applies is not in any federal law but in sixteen state ordinances with their own lists and their own end dates. Some cover only parts of a town, some expire in 2026, others were just extended. We copied every list from the official gazette and counted the municipalities against the official text. If yours is not on the list, the calculator tells you, instead of quietly assuming 15 per cent.

Which cities release their rent index, and which do not

A rent index is an overview of usual local rents, drawn up by the municipality or jointly by tenant and landlord associations. The law requires it to be published; it says nothing about reusing its figures, and cities decide differently. Hamburg publishes the table values as open data under the German open-data licence, and Dortmund publishes its index as an official notice in the city gazette. Berlin publishes its index through the Senate department without any reservation, and the street directory in the official gazette. München, Köln, Frankfurt am Main, Stuttgart, Düsseldorf, Leipzig, Dresden, Hannover, Nürnberg, Bremen, Essen, by contrast, expressly reserve all rights, some with the sentence that the figures may not be stored or offered in electronic systems.

We respect that. For those cities the calculator shows not a single value from the index; it links the city's official online tool, where you place your flat. You enter the result, and from there our calculator does what the city tool does not: it checks whether the rent brake applied in your city on the day you signed, which cap applies, and how much you can reclaim or refuse.

New lease: the rent-brake ceiling

If you sign in a municipality with the rent brake, the starting rent may be at most the reference rent plus ten per cent. For the Berlin example flat that is €481.80 a month; if the landlord asks €620, €138.20 a month is too much. The rent may only be higher if the previous tenant already paid more, if the flat was modernised in the last three years, if it was first let after 1 October 2014, or if this is the first letting after a full modernisation. The landlord must disclose these exceptions in text form before you sign (Section 556g(1a) BGB), otherwise he cannot rely on them.

You only get overpaid rent back after a complaint (Rüge). A complaint within 30 months of the start reaches back to the first day, as long as the tenancy runs; after that, only rent falling due after it counts. The rent brake calculator works through both cases with your figures. We take no share of any refund and refer you to no service that takes a cut.

Rent increase: three limits and two deadlines

During a tenancy the landlord can ask you to agree to an increase up to the reference rent (Section 558 BGB). Three limits apply at once and the lowest wins: the reference rent itself, the cap of 20 or 15 per cent on the rent three years earlier, and the rule that the rent must have stayed unchanged for at least 15 months when the increase takes effect. The letter itself may come no earlier than 12 months after the last increase.

You have until the end of the second calendar month after receipt to agree; the new rent applies from the third. In our example with €600 rent, 60 m² and a reference rent of 12 euros, the reference rent would allow €720, but a 15 per cent cap allows only €690. A letter received on 5 October 2026 can be answered until 31 December 2026. The rent increase calculator gives these dates for your case and the earliest lawful date if the letter came too soon.

Service charges, index and graduated rent

Next to the base rent, service charges (Betriebskosten or Nebenkosten) decide what housing costs. The annual statement must reach you within twelve months of the end of the billing period, otherwise the landlord loses any top-up; you may object for twelve months after receiving it (Section 556(3) BGB). For comparison, the Berlin Senate measured an average of €1.93 per square metre and month for cold service charges in 2024 and €1.50 for heating and hot water. The service-charge check converts your statement to that unit. With an index-linked rent, the rent follows the Federal Statistical Office's consumer price index; the index rent calculator holds the official monthly values up to the latest month published. A graduated rent fixes the increases in advance, but each step must last a year and, under the rent brake, each step is itself capped at ten per cent above the reference rent.

Written for tenants new to Germany

Every page also exists in German. The English pages are written for people who rent in Germany and meet German tenancy terms for the first time, so each German term is explained where it first appears: letters from landlords, property managers and courts will keep using it. The calculators are the same and the figures come from the same official sources.