Extra Mortgage Payment Calculator
Find out what extra principal does to your mortgage. Enter your balance, rate, and term, then add an extra monthly amount to see the time and interest you'd save.
Example: with Loan balance $300,000 · Interest rate 6.5% · Term 30 yrs · Extra per month $200 → Interest saved: $103,449.
- Time saved6 yr 11 mo
- New payoff time23 yr 1 mo
- New monthly payment$2,096.20
Computed by the calculator below using its default values. Change any input to see your own numbers.
Balance: standard vs extra
The power of extra principal
Because mortgage interest is charged on the remaining balance, every extra dollar of principal stops accruing interest for the rest of the loan. Even a modest monthly addition can shave years off a 30-year mortgage and save tens of thousands in interest. The earlier you start, the bigger the effect.
How it’s calculated
The loan is simulated month by month with the extra principal applied; interest and time saved compare it to the original schedule.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Not telling the servicer to apply extra to principal.
- Overlooking better uses like high-interest debt or a match.
Frequently asked questions
Does the extra payment go to principal?
It should — tell your servicer to apply extra amounts to principal, not the next payment, or the savings won't materialize.
Is paying down the mortgage always best?
Not necessarily. Compare the guaranteed 'return' (your rate) against other uses like retirement matching or high-interest debt.
Are there prepayment penalties?
Most modern mortgages have none, but check your loan terms before making large extra payments.