How much extra to pay off early
A $320,000 loan at 6.5% over 30 years costs $2,022.62 a month and $408,141 in interest. To have it paid off in 20 years instead, pay $363.22 extra every month; that saves about $155,500 in interest. In 15 years, it's $764.93 extra a month and saves about $226,400. In 10 years, $1,610.92 extra and about $292,100 saved.
Smaller goals cost less. Paying it off in 25 years takes $138.05 extra a month and saves about $79,900. The target doesn’t have to be whole years either: 17 years 6 months takes $532.44 extra and saves about $191,600.
How the calculator finds the amount
In the Extra payments section, “Pay it off by a date” asks how long you want the loan to last, in years and months. It then finds the smallest extra amount that pays the loan off in time, using the same schedule as everything else on this site: interest charged on what you still owe each month, rounded to the cent. It doesn’t use a shortcut formula. It tries amounts against the full schedule and narrows in until a cent less would miss the date, so $363.22 works for the 20-year goal and $363.21 doesn’t.
Nothing changes in your loan until you choose “Use”, which puts the answer in the extra-payment box so you can see every payment in the schedule. If the loan would already be paid off by your target, it tells you so. On biweekly or twice-a-month payments, the answer is the extra to add to every payment.
Paying off a loan you already have
The calculator starts from a new loan, but you can model the one you have. Enter a price and down payment whose difference is what you owe now, your rate, and the time left as the term. If you no longer pay PMI, set the PMI rate to 0.
Say you owe $250,000 at 6.5% with 25 years left, so a term of 300 months. The regular payment is $1,688.02. To be done in 15 years, pay $489.75 extra a month, which saves about $114,400 in interest. To be done in 10 years, pay $1,150.68 extra, saving about $165,800. Your actual required payment may differ by a few cents from the calculator’s, since your lender set it when the loan began; the calculator shows the method, and your statement shows the exact figures.
Lump sums count too
Expecting a bonus or a tax refund? Pay it toward a particular month in the schedule first. The payoff goal keeps those one-time payments and works out what's still needed every month on top of them, so a lump sum lowers the monthly extra you need.
On the $320,000 loan, a one-time $10,000 with payment 12 brings the monthly extra for a 20-year payoff down from $363.22 to $293.34. Total interest then comes to about $245,800, against about $408,100 with no extra at all.
Paying extra or refinancing to a shorter term
At the same rate, paying a 30-year loan off in 15 years costs almost exactly what a 15-year loan would. A 15-year loan of $320,000 at 6.5% is $2,787.54 a month with about $181,758 of interest. The 30-year loan plus $764.93 extra is $2,787.55 a month with about $181,757 of interest.
The real differences lie elsewhere. A refinance usually has closing costs and may come with a different rate. Paying extra keeps the lower required payment, so you can stop if money gets tight. A 15-year loan commits you to the higher payment. The refinance calculator shows when a new loan would break even, and compare mortgages sets two loans side by side.
Before you commit
- Check your loan has no prepayment penalty, and tell your lender the extra is for principal.
- Paying extra shortens the loan but doesn't lower the required payment. If money gets tight, you can stop paying extra; you can't take back what you've paid.
- Weigh it against other uses for the money: high-interest debt, an emergency fund, or retirement savings with an employer match.
- When you’re ready to make the final payment, ask your servicer for a payoff statement. The payoff amount includes interest up to the payoff date and any fees, so it isn’t the same as the balance on your statement.
Common questions
How can I pay off a 30-year mortgage in 15 years?
Pay enough extra principal each month. On $320,000 at 6.5%, that’s $764.93 a month on top of the $2,022.62 payment. Enter your loan above to find your figure.
How much extra do I need to pay off my mortgage in 10 years?
On a new $320,000 loan at 6.5% for 30 years, $1,610.92 a month. On an existing loan, enter what you owe and the time left, as described above.
What if I can’t keep up the extra payments?
You can stop at any time. The required payment doesn’t change, and the extra you’ve already paid still shortens the loan and cuts the interest.
Is my payoff amount the same as my balance?
No. It adds interest up to the day you pay and any fees owed. Ask your servicer for the exact figure.
Does it work with biweekly payments?
Yes. Choose the payment frequency first and the answer is the extra per payment. The biweekly mortgage calculator explains how biweekly pays off faster, and the extra payment calculator shows what a given extra amount saves.