The one-third rule: the #1 criterion of Swiss agencies

What is the one-third rule?

In Switzerland, the unwritten — and often explicit — convention among agencies is that your monthly net income must be at least three times the monthly rent including utilities (charges).

This is not a law — it's a standardized practice. But in reality, an application that doesn't meet this rule is often rejected without even being read to the end.

Why does this rule exist?

It protects the landlord against unpaid rent. In Switzerland, terminating a lease for non-payment is a long and costly process. Landlords prefer to prevent the risk at the source — and the tenant's solvency is the first indicator used.

The one-third rule ensures that even in difficult times (illness, temporary unemployment), the tenant has enough financial margin to meet their obligations.

Gross or net? Which income counts?

Agencies reason in net income — what actually arrives in your account. For employees, that's the net after AHV, BVG and withholding tax deductions (if applicable).

Income that may be taken into account includes:

• ✓Primary salary (permanent or fixed-term depending on the agency)
• ✓13th month salary (divided by 12, added to the monthly amount)
• ✓Income from a co-tenant or spouse (if co-signing the lease)
• ~Bonuses and premiums (accepted by some agencies, ignored by others)
• ✗Unemployment benefits (rarely accepted without a guarantor)

My situation doesn't meet the one-third rule. What should I do?

This is a common situation, especially for students, young professionals, or people in professional transition. There are legitimate solutions:

• →The guarantor: a third party (often a parent) co-signs the lease and commits their solvency. The agency will also check their income.
• →Bank guarantee: some banks offer rent guarantees. Costly but accepted by most agencies.
• →Transparency in your letter: explaining your situation (e.g. imminent end of training, planned raise) can convince some landlords — but only if the rest of the file is impeccable.

How to present your solvency well in your file

The one-third rule isn't magic: the manager still needs to be able to verify it immediately. A well-constructed file clearly highlights:

• →Monthly net income clearly indicated
• →Last 3 pay slips attached
• →Up-to-date employer's letter
• →Debt certificate (less than 3 months old)

RentalFile automatically calculates whether your situation meets the one-third rule and informs you before you submit your application. You thus have time to adjust your strategy or include a guarantor.

Transparency — your best asset

Never inflate your salary or professional situation. Agencies systematically verify the documents provided and communicate with each other. A falsified file can result in permanent blacklisting on the local rental market — a far more serious consequence than not getting that apartment.

Present your situation honestly, with all the supporting elements. It's the only strategy that works in the long run.