Istanbul remains one of Türkiye’s most active and competitive rental markets. With strong demand from local residents, international professionals, students, and foreign nationals, changes in rental prices and rent increase regulations are important for both landlords and tenants.

In 2026, understanding how the legal rent increase is calculated is especially important. Landlords need to know how much they can legally increase the rent, while tenants should understand their rights before accepting a new rental amount.

This guide explains the 2026 Istanbul rent increase rules, how the legal increase is calculated, and what landlords and tenants should consider when renewing a rental agreement.

How Are Rent Increases Calculated in Türkiye in 2026?

Under Article 344 of the Turkish Code of Obligations, rent increases for renewed rental periods are generally limited by the 12-month average change in the Consumer Price Index (CPI/TÜFE) published by the Turkish Statistical Institute (TÜİK).

This means that there is not one fixed rent increase percentage that applies throughout the entire year.

Instead, the applicable maximum rate changes according to the month in which the rental agreement is renewed.

For example, according to TÜİK’s August 2026 inflation data, the 12-month average CPI increase was 31.79%.

Therefore, for rental agreements renewed in September 2026, the relevant maximum CPI-based increase rate is 31.79%, subject to the specific circumstances of the rental agreement.

2026 Rent Increase Rates

The applicable CPI-based maximum rates have gradually declined during 2026.

For rental agreements renewed during the first nine months of 2026, the rates were:

• January 2026: 34.88%
• February 2026: 33.98%
• March 2026: 33.39%
• April 2026: 32.82%
• May 2026: 32.43%
• June 2026: 32.24%
• July 2026: 32.03%
• August 2026: 31.90%
• September 2026: 31.79%

Rates for October, November, and December 2026 will depend on the relevant CPI data published later in the year.

Therefore, landlords and tenants should always check the latest official inflation figures when the renewal date approaches.

Example of a Rent Increase in September 2026

Suppose a tenant in Istanbul currently pays a monthly rent of TRY 30,000.

If the rental agreement is renewed in September 2026 and the applicable maximum increase rate is 31.79%, the calculation would be:

Current Rent: TRY 30,000
Maximum Increase: 31.79%
Increase Amount: TRY 9,537
New Monthly Rent: TRY 39,537

This example illustrates the CPI-based calculation. The actual legal situation may vary depending on the rental agreement, its duration, previous increases, and other circumstances.

Can a Landlord Increase the Rent Above the CPI Rate?

For ordinary annual renewals covered by Article 344, an agreed rent increase generally cannot exceed the applicable 12-month average CPI rate.

However, this does not mean that the CPI ceiling is the only consideration in every rental relationship.

A particularly important exception concerns rental agreements that have lasted more than five years or are renewed after five years.

In such cases, the determination of a new rent may also take into consideration factors such as:

• The 12-month average CPI change
• The condition of the property
• Comparable rental prices
• Market conditions
• Principles of fairness

Where the parties cannot agree, the rent may ultimately be determined through the applicable legal process.

What Happens After Five Years?

The five-year rule is particularly important in Istanbul because market rents can change significantly over a relatively short period.

For example, a tenant who entered into a rental agreement several years ago may be paying considerably less than the current market rent for comparable properties in the same neighborhood.

After the relevant five-year period, the legal framework allows comparable rental values and the property’s characteristics to become relevant in determining a new rental amount.

However, a landlord should not simply assume that they can unilaterally impose any market rent they choose.

If the landlord and tenant cannot reach an agreement, a legal rent determination procedure may be necessary.

Does the Same Rule Apply Throughout Istanbul?

The legal framework applies across Türkiye, including Istanbul.

However, actual market rental prices vary significantly between Istanbul’s districts and neighborhoods.

Rental values in areas such as Beşiktaş, Kadıköy, Şişli, Sarıyer, Bakırköy, Ataşehir, Üsküdar, Beyoğlu, and Başakşehir can differ considerably depending on the location, building age, transportation access, view, facilities, furnished status, and overall quality of the property.

It is therefore important to distinguish between the legal rent increase limit and the current market rental value of a property.

They are not necessarily the same.

What Should Landlords Know?

Landlords should carefully review the original rental agreement and renewal date before determining a new rent.

The latest applicable 12-month average CPI rate should be checked rather than relying on annual inflation headlines or general market price increases.

Landlords should also keep clear records of rent payments, previous increases, notices, and communications with the tenant.

For long-term rental agreements approaching or exceeding five years, obtaining information about comparable properties in the area can also become important.

What Should Tenants Know?

Tenants should check the applicable legal increase rate before accepting a proposed rent increase.

A landlord’s request should not automatically be considered legally valid simply because rental prices in the surrounding neighborhood have increased substantially.

Tenants should review:

• Their original rental agreement
• The contract renewal date
• Their current monthly rent
• Previous rent increases
• The applicable CPI-based increase rate
• How long the rental relationship has continued

Keeping bank transfer records, contracts, written notices, and communications with the landlord can also be important if a dispute arises.

Can a Landlord Evict a Tenant for Refusing a Higher Increase?

A disagreement about a proposed rent increase does not automatically give the landlord an unrestricted right to evict the tenant.

Eviction of residential tenants in Türkiye is governed by specific legal grounds and procedures.

Landlords and tenants should therefore avoid assuming that a rent disagreement immediately terminates the rental relationship.

Where there is a serious dispute regarding rent determination, eviction, unpaid rent, or contractual obligations, professional legal advice may be appropriate.

Rent Increases for Foreign Tenants in Istanbul

The basic rent increase rules are not replaced simply because the tenant is a foreign national.

Foreign tenants renting apartments in Istanbul should nevertheless pay particular attention to the language and terms of the rental agreement.

The contract should clearly state the monthly rent, payment currency where applicable, deposit, payment date, annual increase provisions, duration, maintenance responsibilities, and other important conditions.

Foreign tenants should also avoid relying solely on verbal agreements with landlords or real estate agents.

Furnished Apartments and Luxury Rentals

Istanbul has a significant market for furnished and luxury rental properties, particularly among expatriates and international residents.

Premium residences, serviced apartments, Bosphorus-view properties, and furnished apartments may have significantly higher market rents.

However, the property’s market value and the legal rules governing increases to an existing rental agreement are separate issues.

This distinction is particularly important when comparing a long-term tenant’s existing rent with the advertised price of newly listed properties.

Why the Renewal Date Matters

One of the most important details when calculating a rent increase is the rental agreement’s renewal date.

The applicable rate depends on the CPI data relevant at the time of renewal.

For example, the maximum CPI-based rate for a contract renewed in January 2026 was different from the rate applicable to a contract renewed in September 2026.

This is why referring simply to the “2026 rent increase rate” can be misleading. The relevant percentage should be determined according to the actual renewal month.

Landlords and Tenants Should Plan Ahead

Istanbul’s rental market can change quickly, but rental relationships remain subject to legal rules and contractual obligations.

Landlords should calculate increases correctly and understand the additional rules that may apply to long-term rental agreements.

Tenants should verify proposed increases and understand their rights before agreeing to significant changes in rent.

Clear written agreements and transparent communication can help prevent many disputes before they escalate.

Professional Real Estate Support in Istanbul

For both local and international clients, navigating Istanbul’s rental market requires an understanding of current market conditions as well as the legal framework.

Whether you are a landlord managing an investment property or a tenant looking for a home in Istanbul, professional real estate support can help you understand market prices, evaluate comparable properties, negotiate rental terms, and manage the rental process more effectively.

With the right information and professional guidance, landlords and tenants can make more informed decisions in Istanbul’s rapidly changing real estate market.

Disclaimer: This article is for general informational purposes only and does not constitute legal, tax, or financial advice. Rent regulations and CPI figures may change. The applicable rate and legal position should be verified according to the rental agreement’s renewal date and the latest official data.