Rent increase in Switzerland: why most increases are challengeable or even void, with a free checker for the permitted maximum, the four-formal-errors nullity check and the ready challenge letter, precise to the 30-day deadline
A letter drops in: your rent is going up. What almost nobody knows, a large share of these increases is challengeable, and a single formal error even makes it completely void, as if it had never existed. If the official cantonal form is missing, the justification is missing, or the same letter threatens a termination, the increase is void by law (Art. 269d CO). Here you check in one minute whether your increase exceeds the permitted maximum, whether it fails on a formal error, and download the ready challenge letter, precise to the 30-day deadline.
💡 When is a rent increase valid, and when is it void?
In Switzerland a rent increase is not an informal letter but a strictly regulated legal act. The landlord may only raise the rent for the next termination date, and must notify the increase at least 10 days before the start of the notice period on a form approved by the canton, with a justification (Art. 269d para. 1 CO). If he fails to, the increase is not merely «somewhat excessive», it is void from the outset.
The sentence that surprises most: void means you need do nothing. An increase without the official form, without justification or combined with a threat of termination has no effect, the rent simply stays the old one (Art. 269d para. 2 CO). If, on the other hand, the increase is formally correct but too high in amount, you must act and challenge it within 30 days at the conciliation authority (Art. 270b CO). It is these two levels, form and amount, that the tools on this page check, for tenants and for landlords who want to get it right from the start.
Only these grounds justify an increase, everything else is abusive and challengeable (Art. 269a CO):
🧮 Is your increase permitted? The ConvivaPlus rent-increase checker
No more guesswork. Enter your current net rent, the increase claimed and the reference-rate figures, and the ConvivaPlus rent-increase checker computes the maximum permitted (rate effect plus inflation plus cost flat rate) and shows with a traffic light whether the claimed increase is permitted or excessive, precise to the franc. No other Swiss portal lays out the three components so openly.
🧮 ConvivaPlus rent-increase checker
Enter net rent, claimed increase and reference-rate figures → maximum permitted increase in % and CHF, plus a permitted / excessive traffic light.
Guide value without warranty. The exact maximum depends on the individual case (date of last fixing, reservations, value-adding investments). For indexed or stepped rents, special rules apply.
How the ConvivaPlus checker calculates: we count the 0.25-point steps from the base reference rate up to the new rate and apply the official increase rate per step (3% below 5%, 2.5% between 5 and 6%, 2% above, VMWG Art. 13), chained multiplicatively. To this we add 40% of your entered inflation and 0.5% per year as a flat rate. The result is the maximum permitted increase per ConvivaPlus, a guide value in line with the practice of the conciliation authorities.
🚦 Is the increase void? The four-formal-errors nullity check
Before arguing about the amount, check the form, because one formal error makes the whole increase void. The ConvivaPlus nullity check takes you through the four decisive questions and tells you whether the increase is formally valid (green), whether it merely shifts (amber) or whether it is void and you simply keep paying the old rent (red).
🚦 ConvivaPlus nullity check
Four questions on the form, and you know whether the rent increase is valid at all.
Was the increase notified on the official form approved by the canton?
Is the increase clearly justified (each ground separately in percent or francs)?
Did the same letter threaten or issue a termination?
Did the form arrive at least 10 days before the start of the notice period?
How the ConvivaPlus nullity check judges: without the official form, without justification, or if the increase is combined with a termination, it is void (Art. 269d para. 2 CO, red). If the form arrived too late, the increase shifts to the next date (amber). If all four points are met, it is formally valid (green), the amount is checked separately. This reading is per ConvivaPlus, derived from Art. 269d CO.
⏱️ By when must you act? The deadline calculator
With rent, timing decides money and rights, on both sides. The ConvivaPlus deadline calculator has two modes: as a landlord you see the last day the form must reach the tenant (at least 10 days before the start of the notice period). As a tenant you see the last day of the 30-day challenge deadline from receipt (Art. 270b CO).
⏱️ ConvivaPlus deadline calculator
Landlord: last day to serve the form. Tenant: last day of the 30-day challenge deadline.
Guide values without warranty. Your specific contract and the locally customary dates govern. Always serve and challenge by registered mail.
How the ConvivaPlus deadline calculator works: the last day of service is the start of the notice period (termination date minus notice period) minus 10 days lead time (Art. 269d para. 1 CO). The challenge deadline is 30 days from receipt (Art. 270b CO). Both are statutory deadlines, presented here per ConvivaPlus.
✉️ Your challenge letter in 2 minutes
The increase is excessive or questionable as to form? Enter your details, and the generator builds you a formally correct challenge to the conciliation authority for tenancy matters: it states the old and new rent, the receipt date, your justification and relies on Art. 270b CO. Download as PDF, sign, send by registered mail, done. You can also copy the text.
🛠️ Challenge-letter generator
Enter the details → ready challenge to the conciliation authority (Art. 270b CO) as PDF or to copy. Free, no sign-up.
📊 The ConvivaPlus increase matrix and the rate history
So you can see at a glance what would be permitted: the ConvivaPlus increase matrixshows how much the landlord may raise the net rent if the reference rate rises again from today's floor (1.25%). Below it, the reference-rate history, from which you can read why a whole wave of increases rolled in 2023, and why purely rate-based increases are hard to justify today.
| Reference rate rises to | Steps from 1.25% | Max. increase |
|---|---|---|
| 1.50% | 1 step | +3.00% |
| 1.75% | 2 steps | +6.09% |
| 2.00% | 3 steps | +9.27% |
| 2.25% | 4 steps | +12.55% |
| 2.50% | 5 steps | +15.93% |
Gross values from the pure rate effect, before inflation and cost flat rate (all steps below 5%, hence 3% per step, chained multiplicatively). Your concrete maximum including inflation is computed by the checker above.
Reference-rate history
Source: BWO-Bekanntgaben (bwo.admin.ch/de/referenzzinssatz)
How the ConvivaPlus increase matrix is built: we count the 0.25-point steps from the current rate (1.25%) and chain the official increase rate of 3% per step multiplicatively (VMWG Art. 13). The history data come, per the ConvivaPlus analysis, from the BWO announcements.
⚠️ The five costliest mistakes, for tenants and landlords
Whoever knows these mistakes loses neither money nor rights, whichever side they are on:
Tenant: sleeping through the 30-day deadline. A formally valid but excessive increase is deemed accepted if you do not challenge within 30 days of receipt (Art. 270b CO). After that you overpay, permanently.
Tenant: not checking the form at all. Without the official form or without justification the increase is void, you would not even need to challenge. Many pay anyway, because they do not know.
Landlord: the wrong form or no official form. A self-typed letter or a form from the wrong canton makes the increase void (Art. 269d para. 2 CO). Always use the current form of your canton.
Landlord: not justifying the increase properly. Each ground (reference rate, inflation, added services) must be broken down separately in percent or francs. A blanket justification does not hold before the conciliation authority.
Both: combining the increase with a termination. Whoever raises and threatens termination in the same letter makes the increase void (Art. 269d para. 2 CO). Always keep the two acts apart.
Most rent increases are challengeable, and a single formal error makes them completely void. Whoever checks, instead of paying, wins.
✅ Step by step: raise or challenge
Here is how to proceed cleanly, whether you are announcing an increase or checking one you received:
The formal-error trick: check form first, not amount. A void increase (no official form, no proper justification, tied to a termination) you never have to challenge, the old rent remains, and you can invoke the nullity without any time limit, not just within 30 days. Many landlords rely on nobody checking the form. That is exactly where your strongest lever lies.
How did you handle a rent increase?
One click – anonymous, no sign-up required.
❓ Frequently asked questions on the rent increase
The key questions on the validity, amount and challenge of a rent increase, answered briefly and concretely.
People also ask
Related questions from our magazine
All information without guarantee. Found an error? → support@conviva-plus.ch
A rent increase in Switzerland is void if it is not notified on the official cantonal form, is not justified, or is combined with a threat of termination (Art. 269d para. 2 CO), and you can challenge a valid increase free of charge within 30 days (Art. 270b CO).
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Discussion
8 voices from the community
Hätte fast blind gezahlt. Die Verwaltung hat mir 120 Franken mehr verlangt, angeblich wegen Teuerung. Mit dem Prüfer kam ich auf maximal 55 Franken zulässig. Angefochten, und bei der Schlichtung haben wir uns auf 50 geeinigt. Ohne diese Seite wären es 70 Franken im Monat zu viel gewesen.
Danke fürs Teilen, Thomas. Genau darum geht es: erst rechnen, dann zahlen. Schön, hat die Schlichtung so sauber geklappt, und gut, hast du die 30-Tage-Frist gewahrt.
Der Nichtigkeits-Check war Gold wert. Mein Erhöhungsbrief war ein normaler A4-Zettel, kein amtliches Formular. Also nichtig. Ich habe der Verwaltung genau das geschrieben, und sie haben die Erhöhung zurückgezogen. Kein Franken mehr bezahlt.
Als Vermieter einer Einliegerwohnung fand ich den Fristen-Rechner im Vermieter-Modus super. Ich hätte das Formular fast zu spät zugestellt, so wäre die Erhöhung ein halbes Jahr später wirksam geworden. Gerade noch rechtzeitig raus.
Merci, Daniel. Genau dafür ist der Vermieter-Modus da. Tipp: Nimm immer das aktuelle Formular deines Kantons, alte Versionen führen schnell zur Nichtigkeit.
Bei mir war die Erhöhung leider korrekt: Referenzzins war bei meinem Einzug tiefer, dazu Teuerung. Der Prüfer zeigte grün. Immerhin weiss ich jetzt, dass es zulässig war, und muss mich nicht ärgern.
Wichtiger Punkt, den ich nicht wusste: Die Erhöhung stand im selben Brief wie eine Kündigungsandrohung, falls ich nicht zustimme. Das macht sie nichtig. Habe es angefochten, die Schlichtung gab mir recht. Diese Verknüpfung ist einfach verboten.
Stark, Marco, und danke fürs Mutmachen. Genau so ist es: Erhöhung plus Kündigungsdrohung im selben Schreiben ist ausdrücklich verboten (Art. 269d Abs. 2 OR) und macht die Erhöhung nichtig.
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