Vienna’s tenant advice service MieterHilfe has launched a free online calculator, the “Wertsicherungsrechner”, that lets tenants check whether a rent increase meets legal requirements. The tool comes as stricter rules limit how far rents may rise, and the city notes that not every increase demanded complies with the law.
How the calculator works
The calculator is available on the MieterHilfe website and is free, anonymous and easy to use. After entering a few details from their tenancy agreement, users receive the permissible rent. It is calculated on the basis of current indexation rules and the rent brake adopted by the federal government last year. If the result differs from the amount charged, tenants are advised to consult MieterHilfe experts. The hotline 01/4000-8000 is available Monday to Friday between 9:00 and 17:00.
What increases are allowed
Rents may in principle be adjusted at most once a year. An increase also requires a valid indexation clause in the tenancy agreement; without one, an indexation-based increase is generally not permitted. The permissible increase depends on the rental segment. In the regulated sector, which includes most older flats and municipal flats, rents may rise by at most one per cent in 2026 and two per cent in 2027. On the free market, inflation of up to three per cent may be passed on in full. Above that level, the rent brake allows only half of the excess to be counted. With annual inflation of 3.6 per cent in 2025, the maximum increase for 2026 is 3.3 per cent.
| Segment | Maximum increase |
|---|---|
| Regulated sector, 2026 | one per cent |
| Regulated sector, 2027 | two per cent |
| Free market, 2026 | 3.3 per cent |
The rent indexation law (Mieten-Wertsicherungsgesetz) applies in principle to main tenancies and subtenancies under the full and partial scope of the Tenancy Act. In non-profit housing it applies only in certain exceptional cases, so the new rules affect only a small share of cooperative flats.
Background
From 1 April 2026, rents in many tenancies could be raised again for the first time this year, but under stricter conditions than before because of the rent brake. MieterHilfe is a City of Vienna service that has been available to tenants free of charge since 1995. It helps with questions about tenancy contracts, problems with deposits and rent increases. Housing councillor Elke Hanel-Torsch described the calculator as a new instrument in the city’s range of advisory services. Christian Bartok, head of MieterHilfe Wien, said the new indexation rules raise questions for many tenants.