See exactly when you'll be debt free — and how much extra payments save you.
The Loan Payoff Calculator shows your monthly payment, total interest and full amortisation schedule for any loan. See exactly how much extra payments save you and when you'll be debt free.
Enter the loan principal, the annual interest rate, the term in years, and any extra monthly payment you plan to make on top of the standard amount. The result panel shows your standard monthly payment, the total interest you'll pay over the life of the loan, the actual payoff date if you keep up your extra payments, and the dollar savings versus the no-extra-payment case. The amortisation table breaks down every monthly payment so you can see exactly how the principal-to-interest ratio shifts over time. Early payments are interest-heavy; later payments knock down principal fast.
The standard fixed monthly payment is M = P × [r(1+r)n] / [(1+r)n − 1], where P is principal, r is the monthly rate (annual ÷ 12), and n is the total months. Each month, interest is principal × r; the rest of the payment reduces principal. Because principal is highest at month one, interest dominates the early payments — that's why a 30-year mortgage takes nearly 20 years to flip to "more principal than interest" territory. Extra payments go entirely to principal, breaking the curve and dramatically shortening the loan.
Round payments up to the nearest hundred — a £312 payment becomes £400 and the extra £88 goes straight to principal. Apply tax refunds, bonuses or windfalls as lump-sum prepayments. Refinance if rates fall by more than 1%. Don't extend the term to lower payments unless cash flow is critical — total interest paid balloons.