Mortgage Affordability Calculator
Mortgages & Home LoansHow much house you can afford: maximum payment, loan, and property price from your income, debts, and down payment.
€206,422
Plus €20,642 in purchase costs
€187,064
Over 30 years at 3.5%
€840.00
Capped by the housing (front-end) ratio
90.6%
Above 80%, many lenders price the loan differently
Budget breakdown
- Down payment
- Loan
- Property price
- Purchase costs
Two stacked horizontal bars comparing the funding side of the budget, down payment plus maximum loan, against the spending side, maximum property price plus purchase costs. The two bars are equal in total.
Rate sensitivity
| Scenario | Rate | Monthly payment | Max loan | Max property price |
|---|---|---|---|---|
| Current rate | 3.5% | €840.00 | €187,064 | €206,422 |
| Rate + 1 point | 4.5% | €840.00 | €165,783 | €187,076 |
| Rate + 2 points | 5.5% | €840.00 | €147,942 | €170,857 |
Happy with the loan size? See its full amortization schedule in the mortgage calculator
How this calculator works
This calculator turns your monthly income, existing debt payments, and down payment into the three numbers a house hunt actually needs: the largest monthly payment you can sustain, the largest loan that payment can service, and the most expensive property the loan plus your down payment can buy. The payment ceiling is the smaller of two constraints: a housing (front-end) ratio that caps the mortgage payment alone, and a total debt (back-end) ratio that caps the mortgage payment plus everything you already pay on other loans. The result always tells you which of the two is binding.
Both ratios are lender conventions, not laws of nature. The often-quoted 28/36 rule and the 43% debt-to-income ceiling from the US qualified mortgage rules are conventions from one market; around 30% of net income is a common rule of thumb elsewhere. Because they vary by country, by lender, and by how income is measured, both ratios are inputs you can adjust rather than fixed rules. The same goes for purchase costs, the one-off taxes, notary, agent, and registration fees of buying: they are entered as a percentage of the price and differ widely between markets, so set them for yours. The maximum price accounts for the fact that these costs scale with the price itself, which is why the affordable price is less than the loan plus the down payment.
The loan figure comes from the standard fixed-rate payment formula solved backwards for the amount borrowed, so it moves sharply with the interest rate: the sensitivity table recomputes everything at one and two percentage points above your rate, a stress test worth taking seriously before committing to a budget. The loan-to-value readout shows how much of the price is borrowed; the calculator does not enforce a minimum down payment, but many banks price loans above 80% loan-to-value less favorably or ask for extra guarantees. Use the result as a realistic budget ceiling, then take the loan into the mortgage calculator to see its full amortization schedule.
Frequently asked questions
- How is the maximum monthly payment calculated?
- It is the smaller of two caps. The housing (front-end) cap is your monthly income times the housing ratio, and it limits the mortgage payment alone. The total debt (back-end) cap is your income times the total debt ratio minus what you already pay on other loans, cards, and car finance. Whichever cap is smaller becomes your maximum sustainable mortgage payment, and the calculator tells you which constraint is binding. If your existing debt payments already use up the whole back-end allowance, no mortgage payment is sustainable at those inputs.
- What are the front-end and back-end ratios, and which values should I use?
- They are the two payment-to-income ceilings lenders use when they assess a mortgage application. The front-end ratio caps the housing payment alone; the back-end ratio caps the housing payment plus all other debt payments. Well-known reference points are the American 28/36 rule of thumb, the 43% debt-to-income limit from the US qualified mortgage rules, and the roughly 30% installment-to-income guideline common among European lenders. All of these are conventions rather than science, and the right values depend on your country, your lender, and whether income is measured gross or net, which is why both ratios are adjustable inputs. The defaults follow a well-known lender convention where the selected currency's home market has one, and otherwise use 30% and 40% of net income.
- How does the calculator turn a payment into a loan and a price?
- The maximum loan is the standard fixed-rate payment formula solved backwards: the principal whose monthly installment at your rate and term equals your maximum payment, P = payment x ((1+r)^n - 1) / (r x (1+r)^n), where r is the monthly rate and n the number of payments. At a 0% rate this is simply the payment times the number of months. The maximum price then solves price plus purchase costs equals loan plus down payment; because the costs are a percentage of the price, the price is (loan + down payment) divided by (1 + the costs percentage).
- Why is the maximum price lower than the loan plus my down payment?
- Because buying costs money beyond the price. Transfer taxes, notary and registration fees, and agent commissions are all charged on top, and most of them scale with the price. With 10% purchase costs, every 110 of budget buys only 100 of property; the other 10 goes to costs. These costs differ enormously between countries, from a few percent to well over 10%, so the calculator treats them as an input you should set for your market rather than a built-in assumption.
- What does the loan-to-value figure mean for me?
- Loan-to-value (LTV) is the loan as a percentage of the property price. At 80% LTV you are borrowing four fifths of the price and covering the rest, plus purchase costs, in cash. The calculator does not enforce any minimum down payment, because rules differ by country, but LTV strongly affects the offer you will get: above roughly 80%, many lenders charge higher rates, require mortgage insurance, or apply stricter checks. If your LTV comes out high, test how a larger down payment or a cheaper property changes it.
- What does this calculator not include?
- It estimates a budget ceiling, not a lender decision. It does not include property taxes, insurance, condominium fees, maintenance, or utilities, which all reduce what you can comfortably pay; it does not model lender-specific underwriting such as credit scores, employment history, or stress-test rates; and it is not a pre-approval. The ratios and purchase costs are conventions you control, not guarantees. Treat the result as the upper end of a realistic search range, and get a real quote before committing to a purchase.
These calculators are for educational purposes only and are not financial advice. Always consult a qualified financial advisor, mortgage professional, or your bank before making a commitment.
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