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Rent reduction calculator: does the reference rate lower your rent?
Swiss rents follow the mortgage reference interest rate published by the Federal Office for Housing. If your rent is still based on a higher rate than today’s, you can ask for a reduction — but only if you ask. Enter your rent and the rate it is based on; the calculator shows your claim and drafts the letter. Everything runs in your browser.
Check your rent reduction claim
Current reference rate: 1.25%, valid since 02.09.2025 (Federal Office for Housing)
Your reduction claim
−2.91%
Reference rate: −2.91% · inflation offset: +0%
New net rent
CHF 1’942
You save CHF 58 a month — CHF 696 a year
Write the request letter
The letter claims the full reduction from the reference rate; any offset is for the landlord to state and justify. Fill in what you like — anything left empty stays as a visible [placeholder]. Nothing you type leaves your browser.
[Ihr Name] [Ihre Adresse] Einschreiben [Vermieter / Verwaltung] [Adresse der Vermieterschaft] [Ort], 11.10.2026 Herabsetzungsbegehren gemäss Art. 270a OR – Mietobjekt [Adresse des Mietobjekts] Sehr geehrte Damen und Herren Mein Nettomietzins von CHF 2’000 pro Monat beruht auf einem hypothekarischen Referenzzinssatz von 1,5 %. Der vom Bundesamt für Wohnungswesen publizierte Referenzzinssatz beträgt seit dem 02.09.2025 1,25 %. Gestützt auf Art. 270a OR und Art. 13 VMWG verlange ich die Herabsetzung des Nettomietzinses um 2,91 % auf CHF 1’942 pro Monat auf den nächstmöglichen Kündigungstermin, d. h. per [nächster Kündigungstermin]. Ich bitte Sie, innert 30 Tagen schriftlich Stellung zu nehmen. Sollten Sie Kostensteigerungen geltend machen, bitte ich Sie, diese im Einzelnen zu beziffern und zu belegen. Freundliche Grüsse [Ihr Name]
Send it by registered mail and keep the receipt: the landlord’s 30-day reply period starts when they receive it.
How the calculation works
The rule comes from the Ordinance on Leases (VMWG, Art. 13): each 0.25-point rise in the reference rate allows a rent increase of up to 3% while the rate is below 5%. A fall works the other way round — it undoes those steps, which is a 2.91% reduction per 0.25 points (1 ÷ 1.03). Several steps multiply: from 1.75% down to 1.25% is 5.74%, not 5.82%. The federal government quotes the same 2.91% in its press releases on the rate.
The landlord can offset part of the claim. Inflation since your last rent change counts at 40% (VMWG Art. 16), and documented increases in maintenance and operating costs may count too. Enter the inflation figure to see its effect; cost increases have no fixed rate, so ask the landlord to itemise them.
These rules do not apply to indexed or graduated (stepped) rents, and subsidised flats often follow their own rules.
Deadlines, what to do if the landlord says no, and how to find your base rate are in the reference interest rate guide.
Frequently asked questions
What is the reference interest rate?
The mortgage reference rate is published every quarter by the Federal Office for Housing. It follows the banks’ average mortgage rate, rounded to the nearest quarter point, and is the basis for adjusting rents to mortgage costs (VMWG Art. 12a).
How do I find the rate my rent is based on?
It is usually stated in the lease or in the last official notice of a rent change. If neither mentions it, ask the landlord which reference rate the current rent reflects.
Does the landlord lower the rent automatically?
No. You have to request it in writing (Art. 270a CO). The landlord has 30 days to reply; if they refuse, agree only in part or do not answer, you can turn to the conciliation authority within another 30 days. The reduction applies from the next termination date.
Can the landlord refuse?
They can offset cost increases since your last rent change: 40% of inflation and documented increases in maintenance or operating costs. They have to back them up with figures — a refusal without figures is not enough.