This calculator shows how much of your monthly mortgage payment goes toward paying principal and how much goes to pay interest over the course of your mortgage.

We've talked about prepaying your mortgage at Get Rich Slowly (see "Should You Prepay Your Mortgage?", "Mortgage Prepayment Made Easy: Own Your Home in Half the Time", and "Ask the Readers: Should I Invest or Prepay My Mortgage?" for example). Find out how much you can save by prepaying some of the principal using this calculator.

Mortgage Calculator
Principal Loan Balance $ (do not use commas)
Interest Rate % See today's average rates.
Last Week Rate
  • 30 yr Fixed DOWN 3.76 % 3.75 %
  • 15 yr Fixed UP 2.94 % 2.95 %
  • 5/1 ARM DOWN 3.28 % 3.27 %
Loan Term Years
Starting Month
Starting Year
Show Full Table?
Monthly Additional Principal
Prepayment Amount
Annual Principal
Prepayment Amount
$ (Enter B for bi-weekly
payment loans)
One-Time Prepayment
...to be paid before (Enter number of payment,
ex. "1" for first payment)