Mortgage repayment calculator — the whole bill, not just the monthly

The monthly payment is the number everyone asks for; the total interest is the number that should drive the decision. This calculator amortises the loan month by month with the Hundred Summers app's own engine — repayment or interest-only — and shows what the term really costs. Your figures never leave your browser.

Reading the numbers like a lender doesn't

Lenders quote the monthly payment because it's the number that fits a budget; the interest share this calculator shows is the number that fits a life plan. At today's rates a typical 25-year loan pays roughly 40% of everything to the bank — and stretching the term to make the monthly “affordable” moves that share steadily higher. The honest comparison is total cost at equal outlay, which is what the overpayment calculator and remortgage calculator price.

One held rate is also a fiction worth naming: real mortgages reprice at every fix's end, and the years after a cheap fix expires are where budgets break. The full Hundred Summers plan carries your actual mortgages through every projected year — rate changes, overpayments, redemption and the payment-free years after — inside the same projection as your pensions and savings, so the “pay it off or invest” question gets answered on your whole position.