Mortgage Calculator
Work out the monthly payment on a repayment mortgage, and what it costs in total.
What this calculates
A repayment mortgage is paid off in equal monthly instalments. Each one covers the interest that has built up since the last payment, and whatever is left over comes off the debt. Because the debt shrinks, the interest share shrinks with it and the capital share grows — the payment itself never changes. This calculator assumes one fixed rate for the whole term. Real deals usually fix the rate for two to five years and then move to a different one, so treat the total interest as the cost if today's rate lasted.
Formula
amount borrowed = price − deposit r = yearly rate ÷ 12 ÷ 100 (the monthly rate) n = years × 12 (the number of payments) monthly payment = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1) at 0%: monthly payment = P ÷ n total repaid = monthly payment × n total interest = total repaid − P
Example
A €300,000 property with a €60,000 deposit means borrowing €240,000. At 3.5% over 25 years that is €1,201.50 a month. Over the full 300 payments you hand back €360,448.97 — so the loan costs €120,448.97 in interest, half the price of the house again.
Frequently asked questions
Why is the first year almost all interest?
Interest is charged on what you still owe, and at the start you owe nearly everything. On a €240,000 loan at 3.5%, the first month's interest is €700 of a €1,201.50 payment, leaving about €501 to come off the debt. As the debt falls the interest falls with it, so the same payment clears more and more capital — by the final year almost all of it is capital.
What does a bigger deposit actually save?
Twice over. You borrow less, so every payment is smaller, and you pay interest on a smaller sum for the whole term. On the example above, another €20,000 of deposit takes roughly €100 off the monthly payment and around €10,000 off the total interest — before counting any better rate a lower loan-to-value earns you.
Does this include fees, insurance or tax?
No. It shows the loan payment only. Arrangement fees, valuation fees, buildings insurance, life cover and any property tax are on top, and they vary by lender and country.
Is a shorter term always better?
It always costs less overall, because interest has fewer years to accumulate — but the monthly payment is higher. The same €240,000 at 3.5% is €1,201.50 a month over 25 years and €1,391.90 over 20, saving about €26,400 in interest for €190 more each month.