Mortgage Amortization Schedule Calculator

A mortgage amortization schedule is a complete table of every payment you will make over the life of your loan — typically 180 payments for a 15-year mortgage or 360 payments for a 30-year mortgage. For each payment, the schedule shows exactly how much goes toward interest, how much reduces your principal balance, and what your remaining balance will be after that payment is applied.

Understanding your amortization schedule reveals one of the most important — and often surprising — truths about mortgage financing: the majority of your early payments go toward interest, not principal. In the first year of a 30-year mortgage at 6.5%, roughly 80% of every payment covers interest charges. This proportion shifts gradually over time. By the midpoint of the loan, the split is closer to 60/40 interest-to-principal. In the final years, nearly the entire payment goes toward reducing the balance.

This front-loading of interest happens because interest is calculated on your outstanding balance each month. When your balance is $300,000, a 6.5% annual rate produces about $1,625 in interest for that month alone. As you pay down the principal, the interest charge drops and more of your fixed payment goes toward the balance. The amortization schedule makes this mathematical reality visible — row by row, month by month.

The schedule is an essential tool for evaluating extra payment strategies. Because extra principal payments reduce the balance you're charged interest on, even modest additional payments in the early years can save tens of thousands of dollars and shave years off the loan term. By running the numbers against your schedule, you can see exactly when your payoff date would move.

Homeowners approaching a refinance decision also benefit from reviewing the amortization schedule. Refinancing resets the amortization clock — meaning if you refinance a 20-year-old 30-year mortgage into a new 30-year loan, you extend your total debt obligation even if the monthly payment drops. The schedule helps you compare the true cost of refinancing versus staying the course.

For borrowers on adjustable-rate mortgages (ARMs), the initial amortization schedule applies only to the fixed-rate period. After the rate adjusts, the remaining balance is re-amortized at the new rate for the remaining term. This calculator assumes a fixed rate throughout the term.