Extra Mortgage Payment Calculator
See how much interest and time an extra monthly principal payment takes off your mortgage.
Free · No sign-up · Your inputs stay in your browser
Your numbers
Price an extra principal payment
Your projection
$88,258 interest saved
Required payment
$1,941.05
Paid off in
22y 0m
Instead of 28 years.
Time saved
6y 1m
Money sent to principal is gone from your emergency fund until the house is sold or refinanced. Fund the cash reserve and any employer match first, and tell the servicer the extra is for principal.
About this tool
Method, assumptions, practical next steps, and limits.
Every extra dollar skips its future interest
Money sent to principal stops accruing interest for the rest of the loan. On a long mortgage, that adds up to more than most people expect.
How the calculation works
The required payment uses the balance, rate and years remaining. The extra amount goes to principal every month until the balance reaches zero.
A $300,000 balance at 6.5% with 28 years left has a required payment of $1,941.05. Adding $200 a month pays it off in about 21 years 11 months, six years sooner, and saves about $88,000 of interest.
The trade-off
Principal payments are illiquid: the money comes back only when you sell or refinance. Before paying extra, fund an emergency reserve, capture any employer retirement match and clear higher-rate debt. Tell the servicer in writing that the extra is for principal, and check the loan has no prepayment penalty.
