Start from the monthly payment you can sustain: the tool turns it into a loan size at your rate and term, adds your down payment, and — if you enter your income — checks the budget against the debt-service share banks typically allow.
Lenders typically cap total debt service around 30–40% of net income and stress-test at higher rates. Your comfortable maximum may be lower than the bank's — a budget stretched to the limit has no room for rate rises or life changes.
Purchase costs (taxes, notary, agent) add roughly 7–15% on top of the price in much of Europe and must usually be paid from savings, not the loan.
Working backwards from a payment answers what a lender will lend, which is a different question from what you should borrow. The bank tests the payment against your income today; it does not know that you plan to drop to one salary, or that the flat needs a roof. Deliberately borrowing below the maximum is what leaves room for both, and it is far easier to do at the offer stage than afterwards — the maximum has a way of becoming the target once it has been named.
Frequently asked questions
How much house can I afford?
Work backwards from the monthly payment you can sustain: banks typically cap total debt service around 30–40% of net income, and your comfortable ceiling may be lower still.
How much down payment do I need?
Commonly 10–20% of the price — plus purchase costs of roughly 7–15% (taxes, notary, agent) in much of Europe, which usually cannot be financed and must come from savings.
What costs come on top of the mortgage payment?
Property tax, buildings insurance, maintenance (budget ~1% of the value per year) and any condominium fees. A budget stretched to the mortgage alone has no room for them.