Mortgage Amortization Calculator With Extra Payments
Extra payments go directly to principal, cutting the balance faster than the standard schedule and reducing total interest over the life of the loan. Even modest additions compound significantly because each dollar of principal removed stops generating interest for every remaining month. Enter your loan details and extra-payment plan above to see the new payoff date.
Your loan and extras
—
instead of —
- Monthly payment
- $0.00
- Time saved
- —
- Interest without extras
- $0
- Interest with extras
- $0
- Interest saved
- $0
Extra payments only help if the servicer applies them to principal. Say so in writing when you send one.
How Extra Payments Reshape the Amortization Curve
In a standard 30-year amortization, the early payments are overwhelmingly interest. On a $250,000 loan at an illustrative rate, roughly 70 percent of the first payment goes to interest and only 30 percent to principal. By year 15, the split approaches 50/50. Extra payments disrupt this curve by accelerating the principal reduction, which lowers the interest charged in the very next period.
An extra $200 per month on that $250,000 loan can shave approximately five to seven years off the payoff date and save tens of thousands in interest, depending on the rate. The impact is front-loaded: the earlier in the loan you start, the more months of avoided interest each extra dollar prevents.
The calculator shows a month-by-month amortization table with and without the extra payment so you can see exactly where the schedule diverges and how the interest component shrinks faster.
Monthly, Annual, or Lump Sum
Monthly additions are the simplest to budget because they become part of your regular payment rhythm. Annual additions — such as directing a tax refund or bonus — deliver a concentrated hit to principal once per year. One-time lump sums, like an inheritance or asset sale, produce the largest single-event impact but are not repeatable.
The calculator accepts all three types simultaneously, letting you model a realistic plan rather than choosing just one. A borrower might add $100 per month, $1,000 each January, and a $5,000 lump sum in year three, then see the combined effect on the payoff timeline.
Before committing extra funds to the mortgage, consider whether your loan has a prepayment penalty — rare on conventional loans originated after 2014 under QM rules, but still present on some older or non-QM products. Also weigh the mortgage paydown against other uses: the extra payment calculator and recast calculator together help you compare paying down principal versus recasting to lower the required monthly payment.
Interest savings depend on the rate, balance, and timing of extra payments you enter. Results assume no prepayment penalty.