Index-Linked Rent Calculator 2026
Pick the current rent, the base month and the comparison month – the calculator derives the new rent from the official consumer price index and checks the twelve-month rule and the payable-from date
As of September 2026Basis: Section 557b BGB, CPI (Destatis)Calculated in your browser – nothing is stored
Usually the base rent excluding utilities – service charges stay out of the calculation.
You can also drag the chart
Check the deadlines24 months since the last change · notice not yet received
New monthly rent
€955.13
€955.13Your rent rises from €800.00 to €955.13 – €155.13 more per month, €1,861.56 per year (index 19.39%).
- Previous rent
- €800.00
- Increase
- + €155.13
- New monthly rent
- €955.13
- Index change
- 19.39%
- Extra cost per 12 months
- €1,861.56
- Adjustment factor
- 1.1939
Legal checkpoints
Twelve-month rule met: the rent has been unchanged for at least 12 months (Section 557b (2) German Civil Code).
The change must be declared in text form and state both the index change that occurred and the new rent or the amount of the increase (Section 557b (3) German Civil Code).
Alongside an index-linked rent, an increase up to the local reference rent under Section 558 German Civil Code is excluded; increases for modernisation and operating costs under Sections 559 to 560 remain possible.
How this was calculated
New rent = current rent × index of the comparison month ÷ index of the base month
The calculator implements the formula of Section 557b German Civil Code. Whether the index-rent clause is valid and which base month applies follows from your tenancy agreement – seek legal advice if in doubt.
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Index-linked rent: the rent follows the consumer price index
With an index-linked rent (Indexmiete) landlord and tenant agree in writing that the rent is determined by the cost-of-living price index for all private households in Germany compiled by the Federal Statistical Office (Section 557b (1) German Civil Code). The benchmark is therefore the consumer price index for Germany – not a local rent index and not the local reference rent.
The maths is a simple ratio: new rent = current rent × index of the comparison month ÷ index of the base month. If the index rises by 10%, the rent rises by 10%. There is no capping limit here as there is under Section 558 – the index is the only ceiling. In exchange the clause works both ways: if the index falls, the rent falls too.
Index-linked rent at a glance
- Agreement in writing
- An index-rent clause must be agreed in writing under Section 557b (1)
- Unchanged for at least a year
- At least twelve months must pass between two adjustments (Section 557b (2))
- Notice in text form
- The change needs text form stating the index change and the new rent (subsection 3)
- No Section 558 alongside
- An increase up to the local reference rent is excluded
How an index-linked increase works out
Four things that sink an index-linked increase
- 1Wrong base monthWhat counts is the base month named in the tenancy agreement, not the month you moved in. If the agreement is silent, the date of conclusion is the usual reference point.
- 2Twelve-month rule not metUnder Section 557b (2) the rent must stay unchanged for at least one year at a time, apart from increases under Sections 559 to 560.
- 3Notice without the index figuresSection 557b (3) requires the index change that occurred and the new rent or the amount of the increase to be stated – text form is enough, but the figures must be there.
- 4Mixing index basesThe consumer price index is rebased every few years (currently 2020 = 100). Both figures must come from the same base, otherwise the ratio is wrong.
- Current monthly rent
- €800.00
- Consumer price index January 2022
- 105.2 points
- Consumer price index January 2026
- 122.8 points
- Index change
- 16.73%
- New monthly rent
- €933.84
- Monthly increase
- €133.84
- Extra cost per 12 months
- €1,606.08
- Current monthly rent
- €1,000.00
- Consumer price index June 2023
- 116.8 points
- Consumer price index June 2026
- 124.6 points
- Index change
- 6.68%
- New monthly rent
- €1,066.78
- Extra cost per 12 months
- €801.36
When the new rent becomes payable
The changed rent is not due immediately. Under Section 557b (3) it is payable from the beginning of the month after next following receipt of the notice. If the notice arrives in February, the tenant owes the new rent from April onwards. The calculator shows that date as soon as you enter the month of receipt.
Alongside an index-linked rent, an increase up to the local reference rent under Section 558 is excluded. Increases for modernisation and for higher operating costs (Sections 559 to 560) remain possible – even within the twelve-month window, because Section 557b (2) expressly carves them out. For the initial rent of an index-rent clause the rent-brake rules (Sections 556d to 556g) continue to apply (Section 557b (4)).
Index rent, stepped rent or reference rent?
A stepped rent (Staffelmiete, Section 557a) fixes the future amounts in the contract – predictable, but disconnected from actual price movements. An index-linked rent ties the rent to inflation instead: in years with low price growth it barely moves, in inflationary years it climbs sharply. Between January 2022 and January 2026 the consumer price index rose by roughly 17%, and an index-linked rent would have risen by the same share.
To see how purchasing power developed overall, use the inflation calculator. Whether a rented property pays off is answered by the rental yield calculator, and the buy-or-rent decision by the rent vs buy calculator. Running costs are estimated by the heating cost calculator, and a move is budgeted with the moving cost calculator.
Frequently asked questions about index-linked rent
Calculation, deadlines, formal requirements and limits
How do I calculate an index-linked rent increase?
New rent = current rent × index of the comparison month ÷ index of the base month. Example: €800 rent, base index January 2022 = 105.2, comparison index January 2026 = 122.8. The factor is 122.8 ÷ 105.2 = 1.1673, so the new rent is €933.84 – an increase of €133.84 per month.
Which index applies to an index-linked rent?
The cost-of-living price index for all private households in Germany compiled by the Federal Statistical Office (Section 557b (1)) – that is, the consumer price index for Germany, currently on the 2020 = 100 base. Regional indices and the harmonised consumer price index are not the benchmark.
How often can an index-linked rent go up?
At most once a year: under Section 557b (2) the rent must stay unchanged for at least one year at a time. Increases for modernisation and for higher operating costs (Sections 559 to 560) are exempt and may be claimed within that window.
From when do I have to pay the increased rent?
From the beginning of the month after next following receipt of the notice (Section 557b (3)). If the letter arrives in May, the new rent is due from July. May and June stay at the previous level.
In what form must the increase be declared?
In text form – an email is sufficient and no signature is required (Section 557b (3)). Substantively the notice must state the change in the price index that occurred and the respective rent or the amount of the increase. Without those figures the notice is ineffective.
Is there a capping limit for index-linked rent?
No. The capping limit of Section 558 (3) only applies to increases up to the local reference rent, and exactly that route is closed for an index-linked rent. The size of the adjustment follows from the index alone. The rent-brake rules still apply to the initial rent, however (Section 557b (4)).
Can an index-linked rent also go down?
Yes. Section 557b determines the rent neutrally through the index and subsection 3 speaks of a "change of the rent". If the consumer price index falls between the base month and the comparison month, the formula produces a lower rent. In practice this is rare – the index last fell in 2020 during the temporary VAT cut.
Index rent or stepped rent – which is better?
It depends on your inflation expectations. A stepped rent (Section 557a) names fixed amounts and is predictable for both sides. An index-linked rent follows actual price movements: in low-inflation years it barely rises, in inflationary years it outpaces a typical step. Both rule out an increase under Section 558.