Mortgage Extra Payment Calculator
This mortgage extra payment calculator shows how much interest and time you save by paying more than your required monthly amount. Enter your balance, rate, term, and extra payment in the calculator above to see your new payoff date. Even a small extra amount each month can shave years off a 30-year loan. The calculator does the math so you can compare scenarios in seconds.
How it's calculated
A mortgage extra payment calculator applies any amount above your scheduled payment directly to your loan principal. Lowering the principal faster means less interest accrues over the life of the loan. That is why a modest monthly extra can save tens of thousands of dollars.
The tool first finds your scheduled principal-and-interest payment. It then adds your extra amount each month and rebuilds the payoff schedule. You see your new payoff date, total interest, and lifetime savings side by side with the original loan.
A worked example
Consider a $350,000 mortgage at 6.5% for 30 years. The scheduled principal-and-interest payment is $2,212.24. With no extra payments, the loan runs the full 360 months and costs about $446,406 in interest. Now add $300 extra every month. In month one, $1,895.83 goes to interest. The scheduled payment puts $316.41 toward principal, and your extra $300 brings the total principal reduction to $616.40. Keeping that $300 going, the loan is paid off in 261 months, about 21 years and 9 months. Total interest drops to $303,412. That is $142,994 saved in interest and 99 months, over eight years, cut from the term.
Common mistakes to avoid
- Not telling your servicer to apply the extra money to principal. The CFPB warns that servicers may otherwise put it toward next month's payment or escrow, so add a written note or use the principal-only option.
- Paying for a third-party biweekly plan. The CFPB notes you can get the same result for free by sending one extra payment a year yourself, instead of paying a setup or service fee.
- Skipping a check for a prepayment penalty before you start. These usually apply only in the first three to five years, but confirm with your lender first.
- Funneling extra cash into the mortgage before higher-rate debt or an emergency fund. Mortgage money is hard to pull back out once it is paid.
- Confusing your total monthly payment with principal and interest. Taxes and insurance in escrow do not pay down the loan, so base your extra payment on the P&I figure.
Frequently asked questions
How much do I save with a mortgage extra payment calculator?
It depends on your loan, but the savings are large. On a $350,000 loan at 6.5% for 30 years, adding $300 a month saves $142,994 in interest and pays the loan off 99 months early. Enter your own numbers in the calculator above to see your figures.
Does one extra mortgage payment a year really help?
Yes. One extra payment a year still cuts roughly four to five years off a typical 30-year loan. A biweekly schedule does the same thing: paying half your amount every two weeks adds up to 26 half-payments, or 13 full monthly payments, each year.
How do I make sure extra payments go to principal?
Tell your servicer in writing to apply the extra amount to principal. The CFPB cautions that without instructions, a servicer may apply extra money to the next payment or to escrow instead of reducing your balance.
Will I pay a penalty for paying my mortgage early?
Usually not for small extra principal payments. The CFPB says prepayment penalties typically apply only if you pay off the whole balance within the first three to five years. Check your loan documents or ask your lender to be sure.
Is a biweekly plan better than just paying extra?
Both reach the same goal, but doing it yourself is free. Third-party biweekly plans can charge setup or service fees. You can match the result by adding one extra payment a year on your own, or using the calculator above to set a monthly extra amount.