Guide
A rent reduction request is a simple written, signed letter to your landlord – no official form is required. It must arrive before the notice period for the next termination date begins, and the landlord then has 30 days to respond.
Under Art. 270a para. 1 of the Swiss Code of Obligations (CO), a tenant may challenge the rent as excessive and request a reduction for the next possible termination date if there is reason to believe the landlord earns an excessive return because the basis of calculation has changed significantly – above all because costs have fallen. The most common trigger is a cut in the mortgage reference interest rate, currently 1.25 %.
How much the rent may fall is set out in Art. 13 of the Ordinance on the Lease of Residential and Commercial Premises (VMWG): with reference rates below 5 %, each 0.25-point step corresponds to 3 % of rent on the way up. Reversed, that gives the reduction rates used in practice – 2.91 % for a 0.25-point cut, 5.66 % for 0.50 points, 8.26 % for 0.75 points. The landlord may offset 40 % of inflation since the last rent adjustment and general cost increases.
The official cantonal form is only required when the landlord raises the rent or changes the lease unilaterally (Art. 269d CO). The tenant's request only needs to be in writing (Art. 270a para. 2 CO). In practice that means:
The letter should be written in German, the language of the lease. Landlords and conciliation authorities in German-speaking Switzerland work in German, and a request they cannot read invites delay.
The reduction takes effect on the next termination date in your lease, observing the notice period – usually three months for flats (Art. 266c CO). The request must therefore reach the landlord before the notice period begins, just like a notice of termination would.
| Termination date in lease | Notice period | Letter must arrive by | Reduced rent from |
|---|---|---|---|
| 31 March | 3 months | 31 December | 1 April |
| 30 June | 3 months | 31 March | 1 July |
| 30 September | 3 months | 30 June | 1 October |
Allow a few days for the registered letter to be delivered. If the lease sets no termination dates, the customary local dates of the canton apply – see notice dates by canton. A request that arrives late is not lost: it simply applies from the following termination date. A retroactive reduction is not possible.
You do not have to calculate the landlord's possible offsets yourself – it is up to the landlord to raise them. Many tenants still include a realistic net figure, because it makes a quick agreement more likely.
Copy the German text below and replace everything in [square brackets]. An English gloss follows.
[Vorname Name Mieter/in 1]
[Vorname Name Mieter/in 2]
[Strasse Nr.]
[PLZ Ort]
Einschreiben
[Name Verwaltung / Vermieter/in]
[Strasse Nr.]
[PLZ Ort]
[Ort], [Datum]
Herabsetzungsbegehren gemäss Art. 270a OR – Mietobjekt [Adresse, Stockwerk, Wohnungsnummer]
Sehr geehrte Damen und Herren
Unser Nettomietzins von CHF [Betrag] pro Monat basiert auf einem hypothekarischen Referenzzinssatz von [z. B. 1.75] %. Das Bundesamt für Wohnungswesen hat den Referenzzinssatz inzwischen auf [z. B. 1.25] % gesenkt.
Gestützt auf Art. 270a OR in Verbindung mit Art. 13 VMWG verlangen wir die Herabsetzung des Nettomietzinses um [z. B. 5.66] % auf den nächstmöglichen Kündigungstermin, den [Datum]. Der neue Nettomietzins beträgt somit CHF [neuer Betrag] pro Monat, gültig ab [Datum Tag nach dem Kündigungstermin].
Bitte teilen Sie uns Ihre Stellungnahme innert 30 Tagen schriftlich mit (Art. 270a Abs. 2 OR). Sollten Sie Gegenpositionen wie Teuerung oder allgemeine Kostensteigerungen geltend machen, bitten wir um eine nachvollziehbare Berechnung.
Freundliche Grüsse
[Unterschrift Mieter/in 1] [Unterschrift Mieter/in 2]
English gloss: "Our net rent of CHF [amount] per month is based on a reference rate of [1.75] %. The Federal Housing Office has since cut the reference rate to [1.25] %. Under Art. 270a CO in conjunction with Art. 13 VMWG we request a reduction of the net rent by [5.66] % as of the next possible termination date, [date]. The new net rent is therefore CHF [new amount] per month from [date]. Please reply in writing within 30 days. If you claim offsets such as inflation or general cost increases, please provide a transparent calculation."
Art. 270a para. 2 CO sets two consecutive deadlines:
If you let the second period pass, that request is spent; you can file a new one for the following termination date. Keep paying the current rent until an agreement or decision is reached. How to proceed after a refusal is explained in Landlord refuses a rent reduction.
If you prefer not to do this yourself: mietzins-senkung.ch calculates the reduction from your lease, prepares the request with the correct deadline and sends it by registered mail for a one-time fee of CHF 39. The calculator is free.
No. The official cantonal form is only required when the landlord increases the rent or changes the lease unilaterally (Art. 269d CO). For the tenant's request a signed letter is sufficient (Art. 270a para. 2 CO).
Generally not. The law requires written form, meaning a letter signed by hand. An ordinary email does not meet that requirement. Send the request by registered mail so you can prove it arrived.
If several people signed the lease, all of them should sign the request. In a joint tenancy, the tenants can in principle only assert rights under the lease together.
A request that arrives too late does not take effect on the missed date, and the reduction cannot be applied retroactively. You can, however, request the reduction for the following termination date.
A termination issued because you assert claims under the lease in good faith can be challenged (Art. 271a para. 1 lit. a CO). During conciliation proceedings, and generally for three years afterwards, additional protection applies.
With reference rates below 5 %, a cut of 0.25 points entitles you to a rent reduction of 2.91 %, a cut of 0.50 points to 5.66 % (Art. 13 VMWG). The landlord may offset inflation (40 % of the CPI increase) and general cost increases. Our free calculator works out the net amount.
This guide explains the general legal position under Swiss tenancy law. It is not legal advice for your individual case. For disputes, contact your cantonal conciliation authority or a tenants' association.