German Rent Increase Calculator
German index rent (Indexmiete): when and by how much can the cold rent legally be raised?
- CPI index integrated
- § 557b BGB compliant
- PDF export
Enter your rental data to calculate the index development
This calculator is for English-speaking tenants and landlords dealing with a German Indexmiete clause. It checks the CPI movement from the contract reference month, applies the chosen threshold and shows the possible cold-rent adjustment.
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Example calculations
Cold rent EUR 1,200, contract reference month three years ago and CPI increase of 8.2% with no higher contractual threshold.
The indexed cold rent would be EUR 1,298.40, an increase of EUR 98.40 per month.
The legal notice still has to state the index change and the new rent or increase amount in text form.
Cold rent EUR 950, contract says adjustment only after 10% CPI movement, current index change 6.4%.
No rent increase is triggered under that threshold yet.
A threshold in the contract can delay an increase even when prices have already moved.
Cold rent EUR 850, contract started January 2020 (base index 105.8), current index 125.5, no contractual minimum threshold.
18.62% index movement, new rent EUR 1,008.29, increase EUR 158.29 per month.
On long contracts the cumulative index increase can outpace the local comparison rent. The landlord still has to declare the change in text form with index values and new amount.
Cold rent EUR 1,100, last index adjustment 8 months ago, current CPI already 4% above the previous reference.
Mathematically an increase would apply, but § 557b para. 2 BGB requires a 12-month gap between adjustments.
The calculator displays the math regardless of timing. The legal effect only kicks in once the minimum interval has passed.
Frequently asked questions
What is an Indexmiete?
An Indexmiete is a German rent clause where the rent follows the consumer price index published by the Federal Statistical Office. The rule is set out in § 557b BGB.
How often can an index-linked rent be increased?
During an Indexmiete, the rent generally has to remain unchanged for at least one year before another index adjustment can take effect.
Which index does the calculator use?
It uses consumer price index data for Germany as the reference for the index movement. The contract may specify a base month or reference date that should be entered carefully.
Does the normal rent cap apply to Indexmiete increases?
The ordinary comparison-rent increase under § 558 BGB is excluded during an Indexmiete. The initial rent and other legal restrictions can still matter.
What must a German index-rent increase notice include?
The notice must be in text form and state the index change plus either the new rent or the increase amount. The changed rent is generally due from the beginning of the month after next.
Can tenants use this calculator to check a landlord letter?
Yes. Enter the original cold rent, reference month and threshold from the contract, then compare the result with the landlord's calculation. Legal advice may still be needed for disputed notices.
When can the landlord ask for the first index adjustment after the contract starts?
The first index adjustment is possible no earlier than 12 months after the contract started. § 557b para. 2 BGB requires a one-year minimum gap between the start of the lease and the first increase, and between any two consecutive index increases.
What if the landlord skipped index increases for several years?
Skipped increases cannot usually be claimed retroactively. The new rent is owed from the second month after the tenant receives the notice. The cumulative index movement does flow into the base/current ratio, but no back-payment is triggered.
Does the index-rent increase notice need to be in writing?
Yes. § 557b para. 3 BGB requires text form. The notice must show the base index, current index, percentage change and either the new rent or the increase amount. Missing any of these makes the notice ineffective.
Which index does the calculator use and where is it published?
The calculator uses the German consumer price index (VPI) with the 2020 = 100 base year, published monthly by the Federal Statistical Office (Destatis). § 557b BGB names this index as the statutory reference for Indexmiete contracts.