Mortgage Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/5/2026
A mortgage's monthly payment is calculated from the amount borrowed, the annual interest rate, and the term. Example: a €200,000 loan at 3.5% over 20 years gives a monthly payment of about €1,159.92, for a total loan cost of €278,380.66 (that is, €78,380.66 in interest).
Explanation
A 'constant-payment amortizing' mortgage — the most common type of home loan — repays the same total amount each month, but the split between interest and principal changes over time: at the start, the payment mostly covers interest (calculated on a still-high remaining balance); toward the end, it mostly repays principal. This calculator shows the monthly payment, the total cost of the loan, and total interest, along with a year-by-year chart of the remaining principal balance. It only calculates the loan itself: borrower's insurance (required in practice, but negotiable separately in France since the 2022 Lemoine law), application fees, and notary fees add to the real cost of the transaction and are not included here. For similar reasoning applied to savings that compound rather than amortize, see the compound interest calculator.
Example: €200,000 borrowed at 3.5% over 20 years
Inputs
Amount borrowed: €200,000. Annual rate: 3.5%. Term: 20 years (240 monthly payments).
Calculation
The monthly rate is 3.5% ÷ 12 ≈ 0.2917%. The payment formula (principal × monthly rate ÷ (1 − (1 + monthly rate)⁻ⁿ), with n = 240 months) gives €1,159.92. Over 240 payments, the total cost of the loan reaches €278,380.66, that is €78,380.66 in interest — a bit more than a third of the amount borrowed.
Result
Monthly payment: €1,159.92/month. Total loan cost: €278,380.66. Total interest: €78,380.66.
Frequently asked questions
Does this calculator include borrower's insurance?
No. Borrower's insurance (covering death, disability, sometimes job loss) is required by nearly all lenders but is negotiated and paid separately from the loan — its cost varies a lot depending on age, health, and the insurer chosen. This calculator shows the payment for the loan alone; add your insurance's monthly cost to get your real total monthly payment.
Why is interest higher at the start of the loan?
Because it's calculated each month on the remaining principal balance, which is at its highest at the start. Since the payment stays constant, the portion that actually repays principal gradually increases — this is what the remaining-balance chart shows: it decreases slowly at first, then faster and faster.
What happens if I repay the loan early?
An early repayment reduces the remaining principal balance, which reduces future interest calculated on it by the same amount. French law caps early repayment penalties (at 6 months of interest or 3% of the remaining balance, whichever is lower); this calculator doesn't model that scenario, it gives the planned schedule with no early repayment.
Should I enter the nominal rate or the APR?
Enter the nominal rate (the interest rate excluding insurance and fees, the one used directly to calculate interest). The APR (annual percentage rate), by contrast, includes insurance and additional fees: it's always higher than the nominal rate and is used to compare offers against each other, not to calculate a monthly payment.