Mortgage affordability and calculation factors in Switzerland

In Switzerland, mortgage affordability is determined by banks using a theoretical interest rate of approximately 5 percent, rather than current market rates, to ensure long-term stability. Key financial criteria include the requirement that housing costs should not exceed roughly one-third of a borrower's gross income.

Standard lending practices typically require a minimum of 20 percent equity, though this amount must also account for additional purchase side costs. A general rule of thumb suggests that under strict scrutiny, the maximum purchase price is approximately 5.5 times a borrower's gross annual income. Factors influencing these calculations include equity levels, mortgage interest rates, the degree of financing, and amortization requirements.