Swiss reference interest rate 2026: cut your rent

The Swiss reference interest rate is 1.25%. If your rent is still based on 1.50% or more, you can ask your landlord for a reduction. How to calculate it and what to do.

Orlando Kahanek · 26 September 2026

The Swiss mortgage reference interest rate has been 1.25% since 2 September 2025 and was confirmed unchanged on 1 September 2026. If your rent is still based on 1.50%, you can ask for a reduction of 2.91%; if it is based on 1.75%, the reduction is 5.66%. You must request the reduction from your landlord in writing; it takes effect on the next termination date, subject to the notice period (Art. 270a CO).

As of 26 September 2026 · Next announcement of the reference interest rate: 1 December 2026

Key points

• Current reference interest rate: 1.25%, in force since 2 September 2025 (Federal Office for Housing, in German; also in French and Italian).
• Who is entitled: tenants whose rent is based on a reference interest rate of 1.50% or more and whose lease is open-ended; if a minimum term applies, at the earliest for the end of that term.
• Amount: 2.91% of the net rent if your rent is based on 1.50%; 5.66% if based on 1.75%, 8.26% if based on 2.00%.
• Deductions: your landlord may offset inflation (at 40%) and documented cost increases.
• Procedure: written reduction request; your landlord has 30 days to respond. If the request is refused, the 30-day period for applying to the conciliation authority runs from receipt of the answer, even if it arrives early. Conciliation is generally free of charge; whether later court proceedings cost anything depends on the canton.
• Protection against termination: a termination given because you assert your rights can be challenged. A three-year protection period only applies after proceedings or after an agreement that settles a dispute.

What is the reference interest rate?

The mortgage reference interest rate is the benchmark for rent adjustments due to changes in mortgage rates. It is based on the volume-weighted average interest rate on mortgages in Switzerland, calculated every quarter, and rounded to the nearest quarter percentage point (Art. 12a VMWG, in German). It is announced quarterly by the Federal Department of Economic Affairs, Education and Research (EAER) and published by the Federal Office for Housing (FOH) at the beginning of March, June, September and December.

On 1 September 2025, the rate was lowered from 1.50% to 1.25%. It has been unchanged since then and was last confirmed on 1 September 2026. It stays at 1.25% as long as the average interest rate does not fall below 1.13% or rise above 1.37%.

Am I entitled to a rent reduction?

As a rule, you are entitled if all of the following apply:

1. Your rent is based on a reference interest rate of 1.50% or more. The relevant rate is stated in your lease or in the form used for the last rent adjustment.
2. You do not have an index-linked or graduated rent that is still running. An index-linked rent follows the Swiss consumer price index for a fixed term of at least five years (Art. 269b CO); a graduated rent rises by amounts set in advance (Art. 269c CO). During that time, the reference interest rate plays no role. When an index-linked lease ends, you must request an adjustment for the lower reference interest rate to take effect at the end of the indexation period, observing the notice period; otherwise you are presumed to accept the current rent (Federal Supreme Court 4A_252/2023, press release in German). Get advice in this case.
3. Your home is protected against abusive rents. Excluded are flats and single-family houses that are luxurious and at the same time have six or more living rooms (not counting the kitchen), as well as subsidised flats whose rent is controlled by an authority (Art. 253b CO). The rules do not apply to holiday homes rented for three months or less (Art. 253a para. 2 CO).
4. Your lease is open-ended (Art. 255 CO). A fixed-term lease ends without notice when the agreed term expires (Art. 266 para. 1 CO); no reduction can be requested during that term. What matters is whether the lease can be terminated with ordinary notice: if there is a minimum term, the next possible date is the end of that term at the earliest.

This applies to residential and commercial premises alike. For commercial premises with a turnover-based rent, the calculation based on the reference interest rate does not simply apply; get advice in this case. If you signed your lease after 2 September 2025 and it is already based on 1.25%, you are not entitled to a reduction.

No reference interest rate in your lease? As a rule, the rate in force when the lease was signed or when the rent was last adjusted applies. The Federal Office for Housing publishes past rates.

Your landlord lowered the rent voluntarily, but not enough? You can then claim the difference (Zurich courts, in German).

How much of a rent reduction can you claim?

Under Art. 13 VMWG (in German), an increase in the mortgage rate of a quarter percentage point entitles the landlord to raise the rent by no more than 3% when mortgage rates are below 5%. When rates fall, rents must be "reduced accordingly". To do this, the increase rates for each quarter point are first added up (3%, 6%, 9% …) and then converted: reduction rate = increase rate × 100 / (100 + increase rate) (Zurich courts, in German). A reduction of one quarter point therefore gives 2.91% (3 × 100 / 103).

The reduction applies to the net rent, i.e. excluding ancillary costs. For several steps, the reduction percentages must neither be added up (not 5.82%) nor applied one after the other (not 5.74%); the correct figure is 6 × 100 / 106 = 5.66%. These values match the table published by the journal "mietrechtspraxis", to which the Federal Office for Housing refers, and apply before any offsetting against cost increases. The Federal Office for Housing lists several rent calculators, including those of the tenants' and homeowners' associations.

What can your landlord offset?

The saving from the lower reference interest rate can be offset against cost increases that have occurred since the last rent adjustment (Art. 13 para. 1 VMWG, in German). In practice, these are mainly:

• Inflation: at most 40% of the rise in the Swiss consumer price index since the last adjustment (Art. 16 VMWG, in German; Art. 269a let. e CO). If the index has risen by 1% since the last adjustment, your landlord may add 0.4%.
• General cost increases for maintenance and operation (Art. 269a let. b CO). In principle, your landlord must prove them by comparing costs over several years; in a dispute, the burden of proof lies with the landlord. Because this is laborious, many conciliation authorities work with flat rates; practice varies from canton to canton, often 0.25% or 0.5% of the net rent per year. In the canton of Zurich, the flat rate is 0% (buildings less than five years old), 0.25% (many ancillary costs billed separately) or 0.5% (few ancillary costs) (Zurich tenants' association, in German). In court, however, the landlord must still prove the cost increases; flat rates are only accepted there in exceptional cases. Ask for a clear breakdown.

It also matters whether earlier changes in the reference interest rate were passed on to you (Art. 13 para. 4 VMWG, in German). Finally, your landlord may argue that the rent does not yield an excessive return (Art. 269 CO); this must be backed up by a clear return calculation. Your reduction may therefore be lower than the figures in the table, or nothing at all.

Step by step: how to request the reduction

1. Check your situation. Look up in your lease or in the last rent adjustment the reference interest rate on which your rent is based, as well as the notice period and termination dates.
2. Work out the date. There is no statutory deadline for the request, but the reduction never applies retroactively: it takes effect on the next termination date (Art. 270a para. 1 CO), observing the notice period. Example: three months' notice, termination dates at the end of every month except December. If your request reaches your landlord by 31 October, the lower rent applies from 1 February.
3. Make the request in writing. Send your reduction request to your landlord in writing (Art. 270a para. 2 CO), ideally by registered mail, which serves as proof. The request must reach your landlord before the notice period begins.
4. Wait for the answer. Your landlord must respond within 30 days (Art. 270a para. 2 CO).
5. Apply to the conciliation authority if necessary. If your landlord refuses or agrees only in part, you can apply to the conciliation authority for tenancy matters within 30 days of receiving the answer. An early refusal starts this period immediately, so do not wait for the response period to end. If your landlord does not answer, or answers after the 30 days, the period runs from the end of the response period; the Federal Office for Housing and the tenants' association recommend sending your application to the conciliation authority no later than 60 days after your original request. The competent authority is the one where the flat or commercial premises are located. No court costs are charged in conciliation (Art. 113 para. 2 let. c CPC) and no party compensation is awarded: if you hire a lawyer, you pay the fees yourself.
6. If no agreement is reached. The conciliation authority may submit a proposed decision. It is deemed accepted if neither party rejects it within 20 days of being notified in writing (Art. 210 and 211 CPC). The party that rejects it receives the authorisation to proceed and must file an action in court within 30 days of its notification; otherwise the proposal is deemed accepted. Without a proposed decision, you receive the authorisation to proceed and can file an action within 30 days of its notification (Art. 209 paras 3 and 4 CPC). Whether court proceedings cost anything depends on the canton: federal law only makes conciliation free of charge, but cantons may go further (Art. 116 CPC). In Geneva, for example, no court costs are charged by the tenancy court; elsewhere, costs may apply.

Template letter: rent reduction request to your landlord

[First names and surnames of all tenants], [address]

By registered mail to: [name and address of the landlord or property manager]

[Place], [date]

Rent reduction request for the flat at [address, floor]

Dear Sir or Madam

The mortgage reference interest rate was lowered to 1.25% with effect from 2 September 2025 (announced on 1 September 2025). My rent is based on a reference interest rate of [1.50%]. Pursuant to Art. 270a CO, I request that the net rent be reduced by [2.91%], from [CHF 2,000] to [CHF 1,942], as of the next termination date, [date].

Please confirm the reduction in writing within 30 days. If you intend to offset inflation or cost increases, please send me a clear calculation with supporting documents.

Yours faithfully

[Signatures and names of all tenants]

Adapt the details in square brackets to your lease. If several people signed the lease, all of them should sign the request. In the example, the new amount equals CHF 2,000 minus 2.91%. Tip: write the letter in the language of your lease.

Common objections from landlords

Do I need to fear termination?

A termination can be challenged if your landlord gives it because you assert claims under the lease in good faith, such as a rent reduction (Art. 271a para. 1 let. a CO).

In addition, a protection period applies: during conciliation or court proceedings and for three years afterwards, if your landlord largely lost, withdrew the claim or reached an agreement with you (let. d and e). An out-of-court agreement that you can prove with written documents also triggers the three-year protection period (para. 2), but only if it settles a dispute. If your landlord grants your reduction request straight away, no protection period arises (BGE 130 III 563).

The protection period does not apply to certain terminations (para. 3), for example for the landlord's urgent own need, for late payment of rent, or when a new owner terminates after a sale; for residential and commercial premises, the new owner must then claim an urgent need for themselves or close relatives or in-laws (Art. 261 para. 2 let. a CO). The intention to sell is not enough. Regardless of the protection period, a termination given in response to your request can still be challenged (let. a).

You must challenge a termination before the conciliation authority within 30 days of receiving it (Art. 273 para. 1 CO). According to common practice, it is enough to hand your application to Swiss Post on the last day of the period; still, do not wait that long.

Watch the start of the period: if you find a collection notice in your letterbox instead of the registered termination letter, the termination is deemed received not when you collect it or when the 7-day collection period expires, but as soon as you could collect it at the post office: as a rule the day after the notice was left, or the same day if you could reasonably be expected to collect it at once. The 30 days start the following day. This also applies if you are on holiday (BGE 140 III 244, BGE 143 III 15). To be safe, count the period from the day the collection notice was left.

Frequently asked questions

Does the reduction also apply to ancillary costs?

No. It applies to the net rent. Ancillary costs are billed separately, either at actual cost or as a flat rate.

Can my landlord raise the rent again later?

Yes, if the reference interest rate rises again. The increase must be notified on the form approved by the canton, with reasons, at least ten days before the notice period begins (Art. 269d CO).

What does the conciliation procedure cost?

Conciliation involves no court fees: in disputes over residential and commercial leases, no court costs are charged and no party compensation is awarded (Art. 113 CPC). If you hire a lawyer, you pay the fees yourself. Later court proceedings may involve costs; some cantons, such as Geneva, do not charge court costs there either (Art. 116 CPC).

When will the reference interest rate change next?

The next announcement is due on 1 December 2026. We will update this article afterwards.

Sources

• Federal Office for Housing: Mortgage reference interest rate (in German; also in French and Italian; retrieved 26.9.2026)
• Federal Office for Housing: press release of 1 September 2025 on the reduction to 1.25% (in German)
• Swiss Code of Obligations (CO), SR 220, version of 1 January 2026 (English translation for information only; the German, French and Italian texts are authoritative)
• Ordinance on the Lease and Usufructuary Lease of Residential and Commercial Premises (VMWG), SR 221.213.11, version of 1 October 2025 (in German)
• Civil Procedure Code (CPC), SR 272, version of 1 July 2026 (English translation for information only)
• Federal Supreme Court: BGE 130 III 563 (agreement under Art. 271a para. 2 CO); BGE 136 III 74 (comparable rents); BGE 140 III 244 and BGE 143 III 15 (start of the period); press release on 4A_252/2023 of 23 November 2023 (index-linked rent, in German)
• Zurich courts (in German): Kostensteigerungen (conversion of reduction rates, burden of proof, flat rates) and Mietzinssenkung
• mietrechtspraxis | mp (in German): Hypothekarzins und Überwälzungssätze (linked by the Federal Office for Housing)
• Swiss tenants' association, German-speaking Switzerland (in German): Mietzinssenkung & Referenzzinssatz (retrieved 26.9.2026) and FAQ of 1 April 2025; Zurich tenants' association: Kostensteigerungspauschale of 30 November 2023
• LAWINFO (in German): Referenzzinssatz – nur unbefristete Mietverträge

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This article provides general information and does not replace advice on your individual case. If you have questions about your lease, the conciliation authority, the tenants' association or a lawyer can help. With RechtsKI, you can ask your tenancy law question and get an answer backed by statutes and case law.