Mortgage / Loan Calculator

Compute the monthly payment on a fully amortising fixed-rate loan and see the full month-by-month amortisation schedule. Add a monthly extra or a one-time lump sum to see how many months and how much interest you save versus the no-extra baseline. Copy or download the schedule as CSV. Pure math in your browser — no upload, no sign-in.

$
%
Extras (optional)
$
$
Monthly payment
—
principal + interest, no extras
Total interest
—
over the life of the loan
Total paid
—
principal + interest + extras
Payoff
—
date of last payment
Saved by extras
—
vs no-extra baseline

Balance over time

Principal Interest Balance

Amortisation schedule

Month Payment Interest Principal Extra Lump Balance

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