Rent increase in Switzerland: is it valid, and how do you challenge it?

A Swiss landlord cannot simply write to say the rent is going up. The increase has to come on an official cantonal form, give reasons, arrive in time before the next termination date — and you then have 30 days to challenge it. Miss one of the landlord’s steps and the increase can be void; miss your deadline and it stands. Check your notice below, then read on.

Check your rent increase notice

The notice

It came on the official cantonal form (not just a letter or email) It states the reasons for the increase It threatens or gives notice of termination

On form and reasons, nothing makes the increase void. Check the dates and the amount below.

Date the notice reached you Date the new rent should apply from Notice period in your lease (months) At least 3 months for flats (Art. 266c CO).

Reference rate before 1.25%1.5%1.75%2%2.25%2.5%2.75%3%3.25%3.5% Reference rate now 1.25%1.5%1.75%2%2.25%2.5%2.75%3%3.25%3.5% Inflation since last rent change (%)

Maximum justified by the reference rate and inflation

+0%

Up to 3% per 0.25-point rise in the rate (VMWG Art. 13) plus 40% of inflation (Art. 16). Anything above needs other reasons — cost increases or improvements — and you can ask for them in figures (VMWG Art. 20).

Where to challenge it Choose your cityZurichGenevaBaselLausanneZugBernWinterthurLucerneSt. Gallen

For other communes, use the authority named on your official form — the form must list it (VMWG Art. 19). All addresses: Federal Office for Housing list

When a landlord may raise the rent

The law protects tenants against rents that bring the landlord an excessive return (Art. 269 CO). An increase is generally not abusive when it is based on one of the grounds listed in Art. 269a CO and the Ordinance on Leases:

• A higher reference interest rate — up to 3% per 0.25-point rise while the rate is below 5% (VMWG Art. 13). The rate is 1.25% today; see the reference rate guide.
• Inflation — up to 40% of the rise in the consumer price index (VMWG Art. 16).
• Cost increases — for example fees, property taxes, insurance premiums or maintenance costs (VMWG Art. 12).
• Improvements that add value — renovations, extensions or energy improvements; a comprehensive overhaul usually counts as 50–70% value-adding (VMWG Art. 14).
• Local customary rents — rents for comparable flats by location, size, fittings, condition and age (VMWG Art. 11).

What the notice must contain

The official form must state the old rent and ancillary costs, the new ones, the date the increase takes effect, and a clear reason — with a separate amount for each reason if there are several (VMWG Art. 19). It must also explain how to challenge the increase and list the conciliation authorities.

The increase is void if the landlord (Art. 269d CO):

1. does not use the official form,
2. gives no reasons, or
3. threatens or gives notice of termination together with it.

A void increase has no legal effect — you do not owe it. Say so to the landlord in writing and keep paying the old rent.

The timing rules

A rent increase can only take effect on the next possible termination date under your lease, and the form must reach you at least ten days before the notice period starts (Art. 269d CO). For flats the notice period is at least three months (Art. 266c CO); your lease may set a longer one.

Example: the new rent is to apply from 1 April 2027, the notice period is three months, so it starts on 1 January 2027. The form must reach you at least ten days before that — around 21–22 December 2026, depending on how the days are counted. The check above flags a notice only when fewer than ten days remain, so it never calls a borderline notice late.

Indexed and graduated rents

Two kinds of lease follow their own rules:

• Indexed rents follow the consumer price index. They are only valid in leases of at least five years (Art. 269b CO), and you can only challenge whether the index change justifies the increase (Art. 270c CO).
• Graduated rents rise by fixed amounts written into the lease — at most once a year, stated in francs, in leases of at least three years (Art. 269c CO). They cannot be challenged during the tenancy (Art. 270d CO).

How to challenge an increase

1. Note the date you received the notice. Your 30-day deadline runs from it (Art. 270b CO).
2. Ask for figures if the reason is cost increases or improvements. You are entitled to a breakdown in numbers (VMWG Art. 20) — but asking does not stop the 30-day clock.
3. Contact the conciliation authority within 30 days, in writing. The check above shows the authority for each city this site covers; for other places, use the one named on your form.
4. Keep paying the old rent. While the procedure runs, the lease continues unchanged if there is no agreement (Art. 270e CO). Conciliation in tenancy disputes costs no court fees (Art. 113 ZPO).

If the reference rate has meanwhile fallen below the rate your rent is based on, you can ask for a reduction in the same procedure — the rent reduction calculator shows how much. And a termination given because the landlord wants to push through an increase can itself be challenged (Art. 271a CO).