The index behind your rent
An index rent in Germany is linked to the consumer price index for Germany (Verbraucherpreisindex, VPI). § 557b BGB still uses its old name: the price index for the cost of living of all private households in Germany. Until 2002, that was indeed its name. Nothing changed in substance with the renaming. In every case, the CPI of the Federal Statistical Office is meant.
What the CPI measures
The CPI shows the average price development of all goods and services that private households in Germany buy for consumption: food, energy, rents, transport, leisure and much more. Every month, statisticians collect prices for a representative basket of goods. How much weight each group of goods carries depends on consumption patterns in the base year.
Do not confuse the CPI with the Harmonised Index of Consumer Prices (HICP). The HICP is used for comparisons within the EU and is not relevant for index rent.
What "2020 = 100" means
The index refers to a base year whose average is set to 100. Currently that is 2020. A value of 125.8 in August 2026 means that consumer prices in August 2026 were 25.8% above the average for 2020. For index rent, however, what counts is not the distance to the base year but the change between two months.
| Year | CPI annual average (2020 = 100) | Change on previous year |
|---|---|---|
| 2021 | 103.1 | +3.1% |
| 2022 | 110.2 | +6.9% |
| 2023 | 116.7 | +5.9% |
| 2024 | 119.3 | +2.2% |
| 2025 | 121.9 | +2.2% |
Monthly values instead of annual values
For index rent, monthly values are usually used, because the adjustment happens at a specific point in time. The Federal Statistical Office publishes the monthly values in its GENESIS-Online database, table 61111-0002. A flash estimate is usually available at the end of the month and the final value around the middle of the following month. The index rent calculator contains the official monthly values from 1995, most recently for August 2026.
Rebasing: when all the numbers change
Roughly every five years, the Federal Statistical Office moves the index to a new base year and updates the basket of goods. The last time was with the publication for January 2023: 2015 = 100 became 2020 = 100. The indices are recalculated from January of the new base year. Earlier results are only formally converted to the new base year.
For your index rent this means: all figures from an older increase, such as 110.0 on base 2015, now appear under a different value in the 2020 = 100 series. So never compare an old value on the previous base with a new value on the current base. The safest approach is to take both months from the current series. Rebasing and rounding can cause the result to differ minimally from an earlier calculation. That is normal.
Where to find the values
- The GENESIS-Online database of the Federal Statistical Office, table 61111-0002 (monthly values).
- The Federal Statistical Office's press releases on the inflation rate, each with the current index level.
- The table in the [index rent calculator](/en/index-rent-calculator), which fills in both months automatically.
Inflation and your budget
The CPI does not just determine your index rent; it also shows how the purchasing power of your income develops. Use the inflation calculator to see what €1,000 from 2020 is worth today. The cost of living calculator gives you an overview of your monthly expenses. The basics of index rent are in our main guide Index rent in Germany.