rent-increase-checker

Explanation & FAQ

This Rent Increase Checker provides a quick orientation for residential rental contracts in Germany. It does not replace legal advice, but helps you visualize typical stumbling blocks in seconds: How much does the net cold rent rise in percent? Does a cap limit apply (20% in three years or – in many cities by state ordinance – 15%)? Does the timing fit the statutory deadlines? And is the demanded rent within the local comparative rent (e.g., Rent Index)?

How to use the tool: Enter your current net cold rent and the demanded new net cold rent. Operating costs/prepayments do not belong in the cold rent calculation. Then select the type of rent increase: "Comparative Rent (§ 558)", "Modernization (§ 559)", "Index Rent (§ 557b)" or "Graduated Rent (§ 557a)". Depending on the selection, the checker shows appropriate additional fields (e.g., Rent Index value, living area, or index values).

Comparative Rent (§ 558): The landlord may demand an increase up to the local comparative rent, but not "as often as they like". By the desired effective date, the rent must have been unchanged for 15 months; furthermore, the increase request may be made at the earliest one year after the last increase. If you enter the receipt date of the letter, the checker calculates the earliest possible due date (upon consent) as the beginning of the third calendar month after receipt. Additionally, you can enter a value from your Rent Index (monthly amount or $/m² × living area). If the demanded new rent is higher, the checker warns you – regardless of the cap limit.

Cap Limit: Even if the Rent Index were higher, the net cold rent may only rise up to the percentage limit within three years. Basically, this is 20%, but in areas with a tense housing market, the limit may be lowered to 15%. Therefore, choose the appropriate percentage limit. The checker transparently shows you the mathematical upper limit and marks if the demand is above it.

Modernization (§ 559): This is not linked to the Rent Index. Basically, the annual rent may be increased by 8% of the allocatable modernization costs. At the same time, a USD cap per square meter applies within six years: maximum 3 $/m² monthly, or maximum 2 $/m² for initial rents below 7 $/m². The tool calculates both limits and takes the lower one. Attention: Pure maintenance must be deducted and subsidies reduce the allocatable costs. For effectiveness, the formal explanation also matters (text form, comprehensible calculation). The tool cannot detect formal errors, but reminds you of typical points in the letter.

Index Rent (§ 557b): With index rent, the Consumer Price Index is the benchmark. During the index rent, the rent must generally remain unchanged for at least one year. The adjustment must be explained in text form and becomes due at the beginning of the month after next following receipt. Enter old and new index values so the checker can output the calculated target rent.

Graduated Rent (§ 557a): With graduated rent, the increases are already in the contract. During the term, increases according to § 558 to § 559b are fundamentally excluded. If an "additional" increase is announced, it is worth looking at the contract and the graduation table.

Practical Tip: Collect documents. For § 558 you need a justification (Rent Index, comparative apartments, or expert opinion). For § 559 you need a cost breakdown and the delimitation from maintenance. If you lack proof or deadlines seem too tight, answer in writing (text form is sufficient) and request the documents. For a binding assessment: Tenants' association or specialist lawyer.

FAQ