Mortgage Amortization Calculator
See how your payments split between interest and principal, year by year.
What This Calculator Does
Builds a year-by-year schedule showing interest paid, principal paid, and remaining balance, then recalculates payoff timing and total interest if you add an extra monthly payment or switch to a biweekly schedule.
Who Is This For
Homeowners who want to see where their payments go, owners targeting an early payoff, and anyone deciding whether extra cash is better applied to the mortgage or elsewhere.
How It Works
Enter your loan amount, interest rate, and term to generate the base schedule, then add an extra payment amount or select the biweekly option to compare against the original plan.
Frequently Asked Questions
Why is so much of an early payment interest?
Interest accrues on the outstanding balance, which is highest early in the loan, so early payments are weighted toward interest and shift toward principal gradually over time.
How does a biweekly payment schedule work?
Paying half the monthly amount every two weeks results in 26 half-payments per year — equivalent to 13 full monthly payments instead of 12 — with the extra amount applied to principal.
How much can extra payments actually save?
Extra principal payments reduce the future interest that would otherwise accrue on that amount, and the savings scale with the size and timing of each extra payment; confirm with your servicer that extra funds are applied to principal.
Is there a prepayment penalty to watch for?
Most standard conforming mortgages carry no prepayment penalty, though some loan types do; check your note or ask your servicer before making large extra payments.