Extra mortgage payment calculator
See how extra principal each month or a one-time payment shortens your loan and cuts interest.
Your numbers
Rates shown are editable examples, not current offers.
Paid off sooner by
6 years, 11 monthsNew payoff in 23 years, 1 month instead of 30 years.
- Scheduled monthly payment
- $1,896
- Monthly payment with extra
- $2,096
- Interest without extra payments
- $382,633
- Interest with extra payments
- $279,185
- Interest saved
- $103,449
Understand this estimate
Uses the scheduled fixed-rate payment for the balance, rate, and years you enter, then adds your extra principal every month and the one-time payment in the month you choose. Interest is charged monthly on the remaining balance. Assumes every extra dollar goes to principal and the rate stays fixed. Check with your servicer how extra payments are applied and whether your loan has a prepayment penalty.
How the calculation works
The calculator first finds the scheduled payment for your balance, rate, and years remaining. Each month it charges interest on the balance, applies the scheduled payment plus your extra principal, and adds the one-time payment in the month you choose. It repeats until the balance reaches zero.
Because interest is charged on the remaining balance, every extra dollar of principal also removes the interest that dollar would have charged in every later month. That is why modest extra payments early in a loan can shorten it by years.
Worked example: $200 a month on a $300,000 loan
A $300,000 balance at 6.5% with 30 years left has a scheduled payment of about $1,896. Paying $200 more each month pays the loan off in 23 years, 1 month instead of 30 years, which is 6 years, 11 months sooner, and cuts total interest from $382,633 to $279,185, saving $103,449. Adding a one-time $10,000 payment in month 12 as well brings the payoff to 21 years, 6 months and the interest saved to $133,153.
Common questions
Will my servicer apply extra money to principal?
Ask how your servicer applies extra payments and whether you need to mark them as principal-only. Check a later statement to confirm the principal balance dropped by the extra amount.
Is there a penalty for paying early?
Check your loan documents for a prepayment penalty. If your loan has one, it may apply only in the first years or above a certain amount.
Do extra payments lower my monthly payment?
Usually not. They shorten the loan instead. Some servicers offer a recast, which recalculates the payment on a lower balance after a large lump sum, often for a fee; ask whether yours does.
Should I pay extra or keep the cash?
Paying down a mortgage earns you its interest rate with certainty, but the money becomes hard to get back out. Many households build an emergency reserve and pay off higher-rate debt first.
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