Frequently asked questions
Trust & basics
What is Rentkompass?
A screening tool that estimates whether a rental listing in Berlin exceeds the Mietpreisbremse ceiling. You paste a listing URL or enter an address, and we show you the estimated legal maximum rent based on the official Mietspiegel.
Who is behind this?
Rentkompass was built by an expat tenant in Berlin who used the Mietpreisbremse on his own apartment. The project is independent - not affiliated with any landlord, property platform, or claims service.
Is this really free?
Yes. The rent check is free. There is no hidden upsell to a legal service. Rentkompass does not take a commission, does not refer you to partner law firms, and does not sell your data.
Is this legal advice?
No. Rentkompass provides estimates based on public data. It is not a substitute for legal counsel. If you want a binding assessment or plan to take action, consult a Mieterverein or a lawyer specializing in Mietrecht.
Do you store my data?
No personal data is stored. Rentkompass has no user accounts and no login. When you check a listing or use the calculator, the inputs are processed in memory and the result is returned. Nothing is saved or tied to you. We do not sell data to third parties. Details are in the privacy policy.
How it works
How accurate is the estimate?
The estimate is based on the same official Mietspiegel data courts use. For most apartments, it is close to what a Mieterverein would calculate. Edge cases exist: unusual apartment features, ongoing modernization, or missing listing data can affect accuracy. We show a confidence indicator when the input data is incomplete.
What data do you use?
The official Mietspiegel (qualified rent index) published by the city, and the Straßenverzeichnis (street register) that maps every address to a location quality tier. For Berlin, this is the Berliner Mietspiegel 2024 with 163 rent table rows and 13,922 street entries.
What is the Mietspiegel?
An official rent index published by the city government. It classifies apartments by building year, size, location quality, and features, and specifies a reference rent range for each category. A qualified Mietspiegel has legal presumption of correctness in court.
Does the rent brake apply to my apartment?
The Mietpreisbremse applies to re-let apartments in designated tight housing markets. In Berlin, that covers the entire city for leases signed since June 2015. New-build apartments (first used and first rented after 1 October 2014) are exempt. So are apartments after a comprehensive modernization, but only for the first re-letting.
What about new-builds and modernized apartments?
New construction after October 2014 is permanently exempt. Comprehensive modernization exempts only the first re-letting after the work. These are the most common exemptions landlords cite. Some claims hold up; many do not. A Mieterverein can assess whether a specific exemption applies.
Taking action
Can my landlord retaliate if I challenge the rent?
Landlords cannot terminate a lease because a tenant invokes the Mietpreisbremse. The law explicitly protects against retaliatory termination. In practice, most landlords - especially large housing companies - handle these cases routinely. A Mieterverein can guide you through the process.
Do I need a lawyer?
Not necessarily. A Mieterverein (tenant association) is the most common first step. Membership costs roughly 50-90 EUR per year, and they can assess your case, draft the formal notice (Ruge), and represent you. If the case goes to court, a Mietrecht lawyer can take over.
What is a Ruge?
A written notice to the landlord stating that the rent exceeds the Mietpreisbremse ceiling. It must be sent before overpaid rent can be reclaimed. Since 2019, a simple written notice is sufficient. A Mieterverein can help draft one.
How long does the process take?
It depends on the landlord. Some agree to a rent reduction within weeks. Others require legal proceedings, which can take months. A Mieterverein can give you a realistic timeline based on the specific landlord and situation.
Where can I get help?
A Mieterverein (tenant association) is the standard path. In Berlin, the Berliner Mieterverein and Mieterschutzbund are the two largest. Membership includes legal consultation and representation for rent disputes. Legal aid (Beratungshilfe) is available for tenants with low income.