Work backwards from a monthly budget
The calculator subtracts living expenses, existing repayments, ownership costs and your chosen monthly cushion from take‑home income. It converts the remaining payment capacity into a loan at the entered rate plus the stress buffer. Savings left after costs and a reserve are then added to estimate a possible property price.
A monthly budget example
With €4,500 of take‑home income, €1,600 of living costs, €300 of existing repayments, €400 of ownership costs and a €400 cushion, payment capacity is €1,800. A higher stress rate supports less borrowing. This household‑budget model provides an indicative estimate and is not a full bank‑approval assessment.
Debt multiples are different from French effort ratios
The displayed multiple compares debt principal with annual gross income. France’s effort ratio compares repayment charges with income. Changing the debt marker adjusts warnings without capping estimated borrowing. The model does not automatically apply the full HCSF framework and does not include a separate borrower‑insurance calculation. Allow for that cost in entered expenses; home insurance is a different category of expense.
Check the target property and cash gap
Usable contribution equals savings less buying costs and reserve, floored at zero. A positive headline budget can therefore coexist with insufficient funds for those costs. The target check compares required cash and the stressed payment, but does not enforce every term, LTV or eligibility rule.