Reference interest rate in Geneva: value, rent reduction or increase, calculator
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The reference mortgage interest rate, the official index for rent adjustments in Switzerland published quarterly by the Federal Office for Housing (OFL), has stood at 1.25% since 2 September 2025. This article sets out, in an updated box, the value in force and the schedule of upcoming publications.
It covers the right to a rent reduction and how to calculate it, with a built-in calculator. The written request to the letting agency (régie) and the landlord's objections are covered, along with the opposite case of an increase when the rate goes back up. The tenant will find the steps to take, the landlord the limits on any increase.
What is the current reference interest rate?
The reference mortgage interest rate is 1.25%, in force since 2 September 2025.
The OFL confirmed this rate at the last three publication dates, on 2 June 2026, 3 March 2026 and 2 December 2025. The average interest rate on mortgage claims used at the 2 June 2026 date is 1.31% (as at 31 March 2026).
The OFL's next two publications are scheduled for 1 September 2026 and 1 December 2026.
This rate is federal: calculated by the Federal Office for Housing, it applies to the whole of Switzerland and no Geneva rate takes its place. It is not to be confused with market mortgage rates, which each borrower negotiates with their bank.
By how much can your rent go down?
Your rent can go down by 2.91% for one quarter-point step of difference from the rate used when it was last set, and by up to 21.26% for the maximum gap of nine steps.
A step is worth 2.91% rather than 3%: the reduction applies to a rent already increased, the increase to the rent as it stood before.
According to the Geneva Cantonal Statistical Office, in May 2025 a 4-room apartment at a free-market rent lets for an average of 1,639 francs per month in the canton. A net rent of that amount, set when the rate stood at 1.75%, opens two steps: the reduction reaches 5.66%, i.e. 92.77 francs per month and 1,113 francs over twelve months.
How do you request a rent reduction from your letting agency?
A rent reduction is requested from your letting agency in writing, in six steps, from noting the starting rate to sending the letter.
- Note the reference interest rate used when the rent was last set, on the official form or the most recent adjustment notice.
- Compare that rate with the rate in force, set at 1.25% since 2 September 2025.
- Convert the difference into quarter-point steps, then apply the formula 3n / (100 + 3n).
- Isolate the net rent, service charges excluded, and convert the resulting percentage into francs.
- Draft the letter with the detailed calculation and the requested effective date.
- Send the request to the landlord or to the letting agency representing them.
Under the Code of Obligations (CO), art. 270a para. 2, the reduction request must be made to the landlord in writing. Written form is all the law requires. Registered mail is a matter of practice: it dates delivery to the landlord.
What the law says (art. 270a para. 1 CO): “The tenant may contest the amount of the rent and demand its reduction as of the next termination date, if they have reason to believe that the leased property yields the landlord an excessive return within the meaning of art. 269 and 269a, because of a significant change in the basis of calculation, resulting in particular from a fall in costs.”
The rent reduction calculator takes up these steps and generates the request letter ready to copy.
Under the Code of Obligations, art. 270a para. 2, the landlord has 30 days to state their position. Their reply opens the question of the date from which the reduction applies to the rent.
What can your landlord raise against the reduction?
The landlord can raise against the reduction offsetting factors provided for by law, which reduce the theoretical decrease without amounting to bad faith.
Six offsetting grounds come up most often in a landlord's reply to a reduction request.
| Ground | Legal basis | Limit or calculation rule | Supporting document to request |
|---|---|---|---|
| Increase in operating costs | CO art. 269a let. b | Actual increase since the rent was last set | Operating accounts |
| Value-adding works | CO art. 269a let. b; OBLF art. 14 para. 1 | 50 to 70% of the cost of major repairs | Invoices and final statement |
| Inflation | CO art. 269a let. e; OBLF art. 16 | 40% of the rise in the Swiss consumer price index | Index at the last adjustment |
| Customary rents in the neighbourhood | CO art. 269a let. a | No numerical limit; comparable properties | Data sheets for the compared dwellings |
| Earlier rent reduction | CO art. 269a let. d | Amount of the payment plan known in advance | Written payment plan |
| Steps already passed on | OBLF art. 13 para. 4 | Deducted from the calculation | History of adjustments |
A landlord who adjusts the rent only partially states, in francs or as a percentage of the rent, the amount of the increase being waived (OBLF art. 18). That statement quantifies the reserve retained and makes the partial reduction verifiable line by line.
What should you do if your landlord refuses the reduction?
Apply to the Conciliation Commission for Leases and Rents within the 30 days following the landlord's reply or, failing that, the expiry of their time limit (CO art. 270a para. 2).
- Refusal: from receipt of the negative reply.
- Partial acceptance: from receipt of the reply.
- Silence: from the expiry of the landlord's 30-day period.
According to the Geneva judiciary, the “Requête en baisse de loyer” (application for a rent reduction) form covers this procedure; filing is done by post or at the counter.
Conciliation involves no court costs (art. 113 para. 2 let. c of the Civil Procedure Code, CPC). If it fails, an authorisation to proceed is issued, which leaves 30 days to bring the case before the Leases and Rents Tribunal (CPC art. 209 para. 4).
The lease remains in force unchanged during the proceedings (CO art. 270e). Notice given because the tenant is asserting in good faith claims arising from the lease may be annulled (CO art. 271a para. 1 let. a).
This protection against notice covers the three years following the end of proceedings in which the landlord was largely unsuccessful, abandoned or considerably reduced their claims, chose not to go to court, or reached a settlement (let. e). Para. 2 extends these three years to a written agreement reached outside proceedings.
Three types of organisation can support the process.
- Tenants' associations: advice on calculating the reduction and representation before the conciliation commission.
- Legal advice services: a one-off consultation to check the request before it is filed.
- Legal expenses insurance: coverage of lawyer's fees and procedural costs, within the limits of the policy.
Can the landlord increase the rent when the rate goes back up?
Yes, the landlord can increase the rent after a rise in the reference interest rate, within the limit of 3% per quarter point, and by notice on the official form approved by the canton.
An increase requires a rent based on a rate lower than the one in force. A rent set when the reference interest rate was already at 1.25% supports no increase until the rate has climbed back to 1.50%.
This ceiling comes from OBLF art. 13 para. 1.
The notice combines four conditions. CO art. 269d para. 1 requires the form approved by the canton, the reasons for the increase and ten days' advance notice; OBLF art. 19 para. 1 details what the form must state, including the old and new rent, the old and new service charges and the date of entry into force.
- The form approved by the canton: the official Geneva form replaces an ordinary letter.
- Precise reasons: each ground is detailed amount by amount.
- Ten days' advance notice: the notice must reach the tenant at least ten days before the start of the notice period for termination.
- The means of contesting: the form carries the conditions for contesting and the Geneva conciliation authorities.
CO art. 269d para. 2 makes void an increase notified without the official form, one given without reasons, and one accompanied by a termination or the threat of one. The tenant applies to the conciliation authority to contest an increase within the 30 days following the notice of increase, under CO art. 270b para. 1.
Which rents fall outside the reference interest rate?
The rents that fall outside the reference interest rate are those under indexed leases and stepped leases.
- Indexed lease: the rent tracks the consumer price index, under CO art. 269b, for a minimum of five years.
- Stepped lease: the rent rises on fixed dates, under CO art. 269c, for a minimum of three years, with at most one increase per year and the increase amount set in francs.
A rent already set on the 1.25% in force since 2 September 2025 remains, for its part, within the mechanism: it opens no gap as long as the rate does not move.
Rents set by the State of Geneva, the boundary between the reference interest rate and the rates charged by banks, and the other parameters that move a Geneva rent complete this framework.
Are subsidised dwellings in Geneva affected?
No, subsidised dwellings in Geneva are not affected: their rent falls under the State aid regime, not the reference interest rate.
The State sets their rent through an approved rent schedule (état locatif agréé) that it controls for as long as the building receives the aid, and on a permanent basis for buildings owned by public-law foundations.
The general law of 4 December 1977 on housing and tenant protection (LGL), rsGE I 4 05, sorts these buildings into three categories in article 16: low-cost housing (HBM), moderate-rent housing (HLM) and mixed housing (HM).
Under article 42 LGL, the approved rent schedule is modified only in the event of a legal reduction in State support or a change in the building's operating conditions, which include variations in the interest rates on mortgage debt. The owner is required to report any fall in those rates to the competent department (para. 4), and the authority may then lower the approved rent schedule (para. 5).
The cantonal vacancy rate stands at 0.31% as at 1 June 2026 (Cantonal Statistical Office). The tightness it measures weighs on each of the rules that govern renting property in Geneva.