Rent Increase Check

The most common rent increase is the one up to the local comparative rent under § 558 BGB. The landlord cannot simply impose it, he needs your consent. Fixed rules apply: the demand must come in text form and give reasons, using the rent index (Mietspiegel), a rent database, an expert report or at least three comparable flats (§ 558a BGB). If your municipality has a qualified rent index, the landlord must always state its values. If that is missing, the demand is formally void, and the tool tells you so in red.

On top of that there are two upper limits. The new rent may not exceed the local comparative rent, and it may rise by at most 20 percent within three years. In municipalities that a state ordinance designates as a tight housing market, the limit is only 15 percent (§ 558 Abs. 3 BGB). Increases for modernisation or service charges do not count. The check recalculates both limits, takes the lower one and shows for the big cities whether the 15 percent cap applies there according to its data. Because ordinances change, every hint asks you to check the current ordinance.

Timing matters too. A new demand is allowed at the earliest one year after the last increase, and the new rent applies at the earliest once the old one has been unchanged for 15 months. You have until the end of the second calendar month after receipt to think it over; the new rent takes effect from the third (§ 558b BGB). Important: silence is not consent. But if you pay the higher rent several times without reservation, that can count as consent. Until the end of the consideration period you can also give extraordinary notice (§ 561 BGB). The check works out all dates and adds them to your deadline tracker with one click.

With an index-linked rent under § 557b BGB the rent follows the consumer price index of the Federal Statistical Office. The check has the official monthly values (base 2020 = 100) built in and recalculates: current rent times new index divided by old index. It checks whether the letter states the index change and the euro amount, whether a year has passed since the last adjustment and from when the new rent is really due, namely from the month after next following receipt. If your contract still names the old base 2015, simply enter the points yourself.

With a graduated rent under § 557a BGB the increases are already in the contract. They must be agreed as euro amounts, with at least one year between two steps. An extra increase based on the rent index or for modernisation is then excluded. After a modernisation the landlord may pass on eight percent of the costs a year (§ 559 BGB), after deducting the repair share and grants, but at most three euros per square metre within six years, or two euros if the rent was below seven euros per square metre. If the modernisation was not announced properly (§ 555c BGB), the increase applies six months later. And if it becomes too expensive for you, there is the hardship objection.

At the end you get a traffic light for every check with its section, the highest rent permitted by your figures, and a finished letter in the German DIN 5008 layout: consent, partial consent up to the permitted amount, a refusal with reasons or a request for evidence. The check fills in the sender from your Amtsprofil if you like; you can edit, print and file the letter in the Aktenschrank. It does not replace advice: in a dispute, a tenants' association that knows your case can help.