Rent Increase vs Annual Inflation in Türkiye

Formula

12-month average change = (average index of the last 12 months / average index of the 12 months before − 1) × 100

annual change = (this month's index / same month last year's index − 1) × 100

maximum new rent = current rent × (1 + 12-month average change)

• Index: TÜİK’s consumer price index (CPI, TÜFE). Its base year has been 2025=100 since January 2026.
• TÜİK publishes both rates every month. Rent uses the 12-month average change of the month before the renewal month (Turkish Code of Obligations art. 344).

Step-by-step example

A home, current monthly rent 25,000 TRY, renewal date 15 September 2026:

1. Find the month before: August 2026.
2. Take TÜİK’s rates for August 2026: 12-month average change 31.79%, annual change 31.51%.
3. Legal maximum rent: 25,000 × (1 + 0.3179) = 32,947.50 TRY. The increase is 7,947.50 TRY.
4. For comparison, with the annual rate: 25,000 × (1 + 0.3151) = 32,877.50 TRY. This is not the legal cap.

This month the two rates are close and the rents differ by 70 TRY. In other months the gap is much larger.

The two rates month by month

A rent of 25,000 TRY with TÜİK data:

The rates come from TÜİK’s consumer price index bulletins; the annual changes were checked against the TCMB table.

Why the two rates differ

The 12-month average takes every month of the last year into account, so it lags behind annual inflation. While inflation falls, the average stays above the annual rate: in August 2025 the average was 39.62% and the annual rate 32.95%. When inflation rises again, the annual rate can pass the average: in May 2026 the annual rate was 32.61% and the average 32.24%.

The legal cap is always the average. The parties may agree on a smaller increase. Residential leases renewed from 11 June 2022 to 1 July 2024 were also capped at 25%; the rent increase calculator applies that cap in this period.