Mortgage repayments
Monthly payments and total interest for any loan, rate and term — plus the effect of regular overpayments.
A repayment mortgage charges interest on the outstanding balance each month; the fixed payment covers that interest first and the remainder reduces the balance.
A repayment mortgage charges interest on the outstanding balance each month; the fixed payment covers that interest first and the remainder reduces the balance. Early on most of the payment is interest, so overpayments early in the term save the most.
The chart shows the balance falling. Overpaying steepens the curve and shortens the term rather than lowering the monthly payment.
Formula
M = P · r(1+r)ⁿ ⁄ ((1+r)ⁿ − 1)
P loan, r monthly rate, n months. Overpayment is added to M each month until the balance clears.
- 01Rate held constant for the whole term; real deals reset at the end of each fixed period.
- 02No fees, insurance or early-repayment charges. Many deals cap penalty-free overpayments at 10% a year.
- 03Overpayment applied every month from month one.
- 04Your home may be repossessed if you do not keep up repayments.
Holding everything else at your inputs
Each row changes one variable and shows the result. It illustrates which assumptions the answer is most sensitive to — it does not suggest which to choose.
| Variable | Changed to | Total interest | vs your result |
|---|
Reminder: this tool is general education, not mortgage advice or a personal recommendation. Your home may be repossessed if you do not keep up repayments on a mortgage. Mortgage advice is a regulated activity — find an FCA-authorised broker or adviser via our toolkit.