Announcing a rent increase: 5 basics for a legally compliant rent increase

For many landlords, a rent increase is part of the regular management of a property. Rising costs, modernizations, or adjustments to the rent index frequently lead to rent being adjusted over the course of a tenancy.

However, for a rent increase to be legally effective, landlords must comply with clear statutory requirements. These include formal requirements, specific deadlines, and comprehensible justifications for the rent adjustment.

In practice, uncertainties often arise: When may a rent increase be announced? Which deadlines apply? And how must a corresponding letter be structured?

In this article, you will learn how landlords announce a rent increase, which legal frameworks apply, and how the process can be structured and organized.

What does a rent increase mean in tenancy law?

A rent increase describes the adjustment of the existing rent during an ongoing tenancy. Landlords may only implement such an adjustment under certain statutory conditions. The basis for this is found in particular in the regulations of the German Civil Code (BGB).

In many cases, a rent increase is carried out to adjust the rent to the local comparative rent or to partially pass on modernization costs. It is important that the increase is comprehensibly justified.

Adjustment to the local comparative rent

One of the most common forms of rent increase is the adjustment to the local comparative rent. In many cities, this is based on the so-called rent index.

The rent index indicates which rents are customary for comparable apartments.

For landlords, this means:

• the current rent may be below the comparative rent

• the adjustment must be justified

• the statutory limits must be complied with

This form of rent increase is particularly common in practice.

Further reasons for a rent increase

In addition to adjusting to the rent index, there are other possible reasons for a rent increase.

These include, for example:

• modernization measures on the property

• increased operating costs in graduated rent agreements

• contractually agreed stepped rent models

Depending on the type of rent increase, different legal requirements apply.

When landlords are permitted to announce a rent increase

A rent increase cannot occur at arbitrary frequency. Tenancy law defines clear time limits.

These regulations are intended to ensure that tenants have sufficient planning certainty.

Waiting period after moving in or after the last rent increase

In principle, a so-called blocking period applies.

This means:

• after a tenant moves in, at least one year must elapse

• a specific period of time must also lie between two rent increases

In practice, this frequently means that a rent increase can be announced after twelve months at the earliest.

Cap limit on rent increases

In addition to the time restriction, there is a so-called capping limit.

This defines how much the rent may increase within a specific period.

Typically, the rule is:

• a maximum 20% rent increase within three years

• in some cities, only 15%

This limit protects tenants from excessive rent increases.

Which deadlines apply to a rent increase

In addition to the waiting period, landlords must also take into account certain deadlines in the course of the rent increase.

These concern both the notification and the effective date of the new rent.

Approval period for tenants

When landlords announce a rent increase, the tenant must first agree to the adjustment.

The tenant generally has until the end of the month after next to make this decision.

Example:

• Receipt of the letter in March

• Consent period until the end of May

Only after this can the new rent take effect.

Timing of the new rent

If the tenant agrees, the new rent is generally due starting from the third month after receipt of the notification.

These deadlines give tenants sufficient time to review the adjustment.

How to correctly announce a rent increase

For a rent increase to be effective, it must meet formal requirements. Errors in the letter can lead to the rent increase becoming legally invalid.

Written notification of the rent increase

A rent increase must generally be made in writing. The letter should be formulated clearly and comprehensibly.

Typical contents include:

• current rent

• new rent

• justification for the increase

• date of the adjustment

Only when this information is complete can the tenant comprehend the adjustment.

Justification for the rent increase

The landlord must provide a comprehensible justification for the rent increase.

Typical justifications are:

• reference to the rent index

• comparison with similar apartments

• modernization measures

The justification is a core component of the letter.

Practical example: Structured process of a rent increase

A housing company manages several hundred apartments and regularly reviews rent levels across its portfolio.

In the past, rent increases were often organized manually. Information was stored in different documents, and letters were drafted individually.

This led to:

• high administrative effort

• confusing documentation processes

• increased coordination requirements within the team

Through structured processes and digital document management, these workflows could be improved.

Result:

• more efficient creation of rent increase letters

• better documentation of rent adjustments

• structured communication with tenants

How digital processes can support landlords

Digital solutions help real estate companies organize administrative processes more efficiently. Digital systems can also provide support with lease agreements and document management.

Structured document management

Digital real estate platforms enable the centralized management of documents.

Among other things, this facilitates:

• management of tenancy agreements

• creation of documents

• traceability of changes

As a result, administrative processes can be better organized.

More efficient letting processes

In addition to contract processes, digital solutions can also structure letting processes.

Typical features include:

• management of prospective tenants

• scheduling for viewings

• structured documentation of tenancies

Learn more about digital letting processes here:

Letting real estate professionally: How EverReal revolutionizes the letting process

Digital contract processes are also becoming increasingly important:

Digital signatures in tenancy agreements: Advantages, legal aspects, and implementation

A rent increase must be carefully prepared and correctly announced. Landlords must observe both legal prerequisites and formal requirements.

Comprehensible justifications, clear deadlines, and structured communication with tenants are especially important.

Digital processes and structured property management can help organize tenancies efficiently and simplify administrative tasks.

When is a landlord allowed to announce a rent increase?

In principle, a rent increase can be announced at the earliest twelve months after the start of the tenancy or after the last rent increase.

Which deadline applies for agreeing to the rent increase?

Tenants generally have until the end of the month after next to agree to the rent increase.

How must a rent increase be announced?

The rent increase must be made in writing and contain a comprehensible justification, for example by referring to the rent index.

What reasons exist for a rent increase?

Common reasons include adjustment to the local comparative rent, modernization measures, or contractually agreed stepped rents.