Rent Reduction: Sample Letter and Calculation

The reduction request under Art. 270a CO: fill-in sample letter, official reference-rate history, calculation example and mailing checklist.

Checked on 21 August 2026 by Jens Herbst, BoVitaWe keep every document current and check it regularly against the sources.

Who is this document for?

For tenants whose rent is still based on a higher reference rate than the current one and who do not want to give money away.

What is inside

  • Fill-in sample letter citing Art. 270a CO
  • Official reference-rate history (from our maintained, date-checked source)
  • Quick check: are you entitled at all?
  • Calculation example with the per-0.25-points rule of thumb
  • Mailing checklist and what to do if the landlord refuses

How to fill it in

  1. 1Do the quick check first; five questions show whether the request is worth it.
  2. 2Replace every [bracket field] in the letter; the calculation page supplies the numbers.
  3. 3Save as PDF and send by registered mail, not email; the checklist walks you through mailing.

Frequently asked questions

For tenants across Switzerland whose contract or last rent adjustment is based on a higher reference rate than the current official value; the quick check clarifies it in five questions.

The letter is based on Art. 270a CO and contains everything a management expects. It becomes effective with your correct details, your signature and timely registered mailing.

The request takes effect at the next ordinary termination date; send it as early as possible by registered mail. The kit explains the date logic for your contract.

To your landlord or the responsible management, by registered mail to the address in your lease; the mailing checklist covers the details.

You then have 30 days to involve the conciliation authority; the kit describes the refusal procedure step by step.

If the template alone is not enough

In-depth guideReference interest rate 1.25 percent, rent reduction in Switzerland, how to request it properlyThe article goes deeper than the document: deadlines, examples and where to turn.

What this document is based on

Every provision is checked against the wording of the consolidated version. The links lead straight to the federal statute.

  • OR Art. 270a · Herabsetzung des Mietzinses

    Tenants may request a reduction to the next possible termination date if the calculation basis has changed materially, for example through a fall in costs. The request must be in writing and must reach the landlord BEFORE the notice period starts. The 30 days in this provision are the LANDLORD's deadline to respond, not the tenant's filing deadline.

    OR Art. 270a Abs. 1 und 2, SR 220 · Status 01.01.2026

When the document alone is not enough

In tenancy matters the conciliation procedure is free of charge. You need no lawyer, and the authority also gives advice.

Find the conciliation authority of your cantonSwiss Tenants' AssociationAdvice, fact sheets and template letters (in German)

Looking for a room, not just documents?

BoVita rents furnished shared rooms with all-in rent in Aarau, Wohlen, St. Gallen and Brugg. Reply within 48 hours on working days.

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