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.
Balance: standard vs extra
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Get itThe 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.
Worked example
Adding $200/month to a $300k, 6.5%, 30-year loan saves ~$103k interest and pays it off years early.
Common mistakes
- Not telling the servicer to apply extra to principal.
- Overlooking better uses like high-interest debt or a match.
Where it is used
- Seeing the payoff impact of extra principal.
- Choosing an extra-payment amount.
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.
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