Calculator
Mortgage amortization calculator
Every mortgage payment is part interest, part principal — and the mix shifts every month. This calculator builds your full amortization schedule so you can see exactly how the balance falls and how much interest the loan really costs.
How to read your amortization schedule
Look at the first row and the last: at the start, the interest column dwarfs the principal column; by the end it's reversed.
That front-loading is why the first years of a mortgage build equity slowly — and why extra principal applied early has such an outsized effect. Every dollar of early principal erases all the future interest that dollar would have accrued.
- Payment: stays constant every month for the whole term.
- Interest: largest at the start, shrinking as the balance falls.
- Principal: tiny early on, then the growing share of each payment.
- Balance: what you still owe after each payment.
Before refinancing, check the break-even calculator; to see the effect of paying extra, use the payoff calculator.
Frequently asked questions
What is an amortization schedule?
A month-by-month table showing how each mortgage payment splits between interest and principal, and how your balance falls over time. Early payments are mostly interest; the principal share grows every month until the loan is paid off.
Why is so much of my early payment interest?
Interest is charged on the outstanding balance, which is largest at the start. On a 30-year loan at today's rates, more than half of your first few years of payments go to interest — which is why paying extra principal early saves so much, and why refinancing resets that clock.
How can I pay less interest over the life of the loan?
Shorten the term (a 15-year loan cuts lifetime interest by more than half), add extra principal each month, or make biweekly payments. Even $100 extra a month on a $250,000 loan can cut years off the schedule — try it in the payoff calculator.