What is an index-linked rent?
With an index-linked rent (Indexmiete), the rent is tied to the consumer price index for Germany (CPI, German VPI) published by the Federal Statistical Office (§ 557b BGB). If living costs rise, the landlord can adjust the rent in the same proportion. If they fall, the tenant can request a reduction.
The agreement must be in writing in the lease. Only the CPI for Germany is permitted, no other index.
- Alongside an index-linked rent, no increase to the local comparative rent under § 558 BGB is possible.
- An increase for modernisation is only possible for building measures the landlord is not responsible for.
- Applies to privately financed housing. Commercial property, rent-controlled housing and student or care homes are not covered.
How to calculate the new rent
The rent changes in percentage terms in the same proportion as the index. CIRO calculates without rounding the percentage in between and rounds only the new rent to the cent.
New rent = current rent × new index value ÷ old index value
Common mistake: the point difference is not the percentage change. If the index rises from 114.3 to 122.8 points, that is 8.5 points but only 7.44%.
Worked example
The net cold rent is €850. At the last adjustment, the CPI was 114.3 points in January 2023; in January 2026 it was 122.8 points.
- Change: 122.8 ÷ 114.3 = 1.07437, i.e. + 7.44%.
- New rent: €850 × 122.8 ÷ 114.3 = €913.21.
- Increase: €913.21 − €850 = €63.21 per month.
Current CPI values
The table shows the consumer price index for Germany, overall index, on base 2020 = 100. As the new index level, use the latest month published before your statement. The Federal Statistical Office usually publishes the final monthly value around the middle of the following month.
Consumer price index for Germany (2020 = 100)
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 122.8 | 123.1 | 124.5 | 125.2 | 125.0 | 124.6 | 125.6 | 125.8 | 126.6 | – | – | – |
| 2025 | 120.3 | 120.8 | 121.2 | 121.7 | 121.8 | 121.8 | 122.2 | 122.3 | 122.6 | 123.0 | 122.7 | 122.7 |
| 2024 | 117.6 | 118.1 | 118.6 | 119.2 | 119.3 | 119.4 | 119.8 | 119.7 | 119.7 | 120.2 | 119.9 | 120.5 |
| 2023 | 114.3 | 115.2 | 116.1 | 116.6 | 116.5 | 116.8 | 117.1 | 117.5 | 117.8 | 117.8 | 117.3 | 117.4 |
| 2022 | 105.2 | 106.0 | 108.1 | 108.8 | 109.8 | 109.8 | 110.3 | 110.7 | 112.7 | 113.5 | 113.7 | 113.2 |
| 2021 | 101.0 | 101.6 | 102.1 | 102.4 | 102.6 | 102.9 | 103.4 | 103.5 | 103.8 | 104.3 | 104.5 | 104.7 |
| 2020 | 99.8 | 100.1 | 100.3 | 100.4 | 100.4 | 100.5 | 99.7 | 99.7 | 99.7 | 99.9 | 99.7 | 99.8 |
About every 5 years, the Federal Statistical Office moves the CPI to a new base year and republishes all values. Always take both values for an adjustment from the same base. If your lease refers to a value on an old base, enter both values manually. Destatis offers a rebasing calculator for this.
Form, waiting period and date
- The rent must remain unchanged for at least 1 year (§ 557b (2) BGB). Increases under §§ 559, 560 BGB do not count.
- The adjustment is made by a statement in text form. It states the change in the index and the new rent or the increase as an amount of money (§ 557b (3) BGB).
- The new rent applies from the start of the month after next following receipt of the statement. If it arrives in October, the new rent applies from 1 December.
- For a rent increase under § 558 BGB it would only be the third month after receipt. An index-linked rent therefore takes effect one month earlier.
Whether the statement may arrive before the year has passed, as long as the new rent only applies afterwards, has not been conclusively settled. CIRO therefore shows you the safe route: a receipt date for which the month after next falls after the end of the year.
Special cases
- Index fallen: the tenant can request a reduction. The calculator then shows a negative change.
- Contractual threshold: if the lease says the rent is only adjusted from a certain change, or prescribes rounding, the lease applies.
- Rent brake: in areas with a rent brake, the limit applies to the initial rent at the start of the lease (§ 557b (4) BGB). Later adjustments follow the index.
Planned change for tight housing markets
A draft bill by the federal government provides that in tight housing markets, a CPI increase of more than 3% per year should only be passed on to the rent by half. It has not been passed yet (as of 14 Oct 2026). The calculator follows current law.