How does the Mortgage Calculator work?
The loan amount is the price minus your down payment. From this the monthly annuity over the term is calculated.
Background & details
The result shows the monthly payment, the loan amount and the total interest over the term. On a mortgage the interest total is often startling – over 25 or 30 years it can reach half the purchase price. That is why every tenth of a percentage point on the rate and every year shaved off the term matters so much.
What are typical values?
Most lenders expect at least 20 % down plus the buying costs (transfer tax, notary, agent fees – which can add 10–15 % on top of the price in some markets). Your monthly payment should generally stay below 30–35 % of net household income. An initial repayment (amortisation) of at least 2–3 % per year keeps the loan on track to be cleared in a realistic timeframe.
Common mistakes
- Forgetting closing costs: The calculator shows the loan only. Taxes, notary and agent fees must be paid on top, usually from your own cash.
- Ignoring the fixed-rate period: If the rate is fixed only for part of the term, you will need follow-on financing at an unknown future rate – a genuine risk.
- No buffer: Maintenance, service charges and reserves come on top of the payment.
Practical tips
Run several scenarios: compare 20 % versus 30 % down and watch how much the payment and the interest total fall. Raise the repayment rate and see the term shorten by years. Plan conservatively – budget for a rate you could still afford once any fixed-rate period ends, and lock in a long fixed period while rates are low.
When to use it – and when not
This calculator gives a solid first estimate for an annuity mortgage with a level payment. It is not a substitute for real advice: subsidised loans, variable rates, extra-repayment rights and the exact remaining balance after a fixed-rate period belong in a binding lender offer. Use these figures to compare deals, not as a final commitment.