SARON or fixed rate comparator: simulate both
Enter the amount, the term and the margin: the comparator prices both solutions side by side.
Your financing
Assumption: compounded SARON at 0%, interest estimated excluding amortisation. Actual cost varies with the market.
How to read the gap
The SARON rate is made up of two parts: SARON itself, which follows the Swiss National Bank's policy rate and moves continuously, and the bank's margin, fixed in the contract and stable for the whole term. Only the first one moves. The margin is therefore the real subject of negotiation.
The fixed rate buys certainty: the monthly instalment does not change, whatever happens to rates. The cost gap between the two solutions, at the date of the simulation, is the price of that certainty. It is not a loss, it is an insurance premium.
What the simulation does not say
The calculation assumes a constant SARON for the whole term, which never happens. It gives an order of magnitude, not a forecast. It also ignores the household's ability to absorb an increase: that, not the cost gap, is what decides in practice.
How SARON works, how it has moved and the criteria for choosing between the two formulas are covered in the guide to the SARON mortgage.