How to use the mortgage payoff calculator
- Enter your current mortgage balance, the interest rate and your monthly principal and interest payment from your latest statement. Leave out escrow for taxes and insurance.
- Enter the date of your next payment. It sets the calendar for the payoff date.
- Choose what to find out: what happens if you pay extra each month, or how much extra is needed to pay off by a target number of years and months.
- Optional: under More options, add a one-time payment you can make now.
- Read the payoff date, the payments left, the interest saved and the table that compares other extra amounts. Download the CSV or PDF for the month-by-month plan.
Formula
Each month: interest = balance x r (r = APR / 12), rounded to the cent
Balance after a payment = balance + interest - payment - extra
Payments left without extras: n = -ln(1 - B x r / P) / ln(1 + r), rounded up, where B is the balance and P the payment
Payment needed to finish in n months = B x r / (1 - (1 + r)^-n)
Extra needed = payment needed - your current payment
The closed form for the number of payments only works when the payment is larger than the first month of interest, B x r. The calculator rejects smaller payments because the balance would never fall. The schedule itself is simulated month by month, so the last payment is whatever clears the balance.
Worked examples
Your current path: a $250,000 balance at 6.5% with a $1,800 payment and the next payment on November 9, 2026 needs 259 payments (21 years 7 months) and ends on May 9, 2048. Interest still to come is $215,023.43. The closed form agrees: n = -ln(1 - 1,354.17 / 1,800) / ln(1.0054167) = 258.4, rounded up to 259.
An extra $250 each month: the loan ends after 201 payments, on July 9, 2043. Interest falls to $160,028.64, which saves $54,994.79 and 58 payments. Other amounts on the same loan: $100 extra ends it on January 9, 2046 and saves $26,326.09; $500 extra ends it on July 9, 2040 and saves $86,688.47; $1,000 extra ends it on January 9, 2037 and saves $122,445.30.
A lump sum plus $250: a $20,000 payment now, followed by $250 extra a month, ends the loan after 174 payments on April 9, 2041 and saves $89,904.24.
A target of 15 years: a payment of $2,177.77 clears $250,000 in 180 months, which is $377.77 more than the $1,800 payment. The loan ends on October 9, 2041 and saves $73,025.28 of interest.
Why a small extra payment changes the date so much
Early in a mortgage most of the payment is interest, and the principal portion is small. An extra payment goes straight to principal, which lowers the balance that interest is charged on for every later month. The effect compounds: the interest you avoid also frees more of each later payment to reduce principal. On the example loan, $250 a month moves the payoff date forward by almost five years.
The savings fall off the longer you wait. An extra payment made in the final years removes interest for only a few months, so the same dollars do far less.
Extra monthly payments versus a lump sum
A lump sum works immediately, because it lowers the balance before the next payment. A series of small extras works gradually. The plan above lets you combine both. If you are considering a lump sum, the mortgage recast calculator shows the alternative of using it to lower the monthly payment instead of ending the loan sooner.
Things to confirm with your servicer
Ask whether extra money is applied to principal right away, whether the loan has a prepayment penalty, and how to designate an extra principal payment on a statement or online. For an official payoff figure on a specific date, request a payoff quote from your servicer. It includes interest accrued up to that date and any fees, which this estimate does not.
This tool does not say whether paying off a mortgage early is right for you. That depends on your other debts, your savings and your plans, so compare the interest rate on the mortgage with your other options.
Assumptions and limits
- A fixed-rate loan. Payments are made on time, one per month, and the first one in the plan is due on the next payment date you enter.
- Interest is the balance times APR / 12, rounded to the cent each month. Daily-interest loans can differ slightly.
- Extra money, including a one-time payment, is applied entirely to principal in the month it is paid. A one-time payment is applied before the next regular payment.
- The payment you enter is principal and interest only. Escrow for taxes and insurance, PMI, late fees and penalties are not included.
- The result is an estimate, not an official payoff quote. Your servicer's quote for a specific date is the amount needed to close the loan.
- Loans that would take more than 100 years at the entered payment are rejected as unreasonable.
Frequently asked questions
How do I find my mortgage payoff date?
Enter the balance, rate and monthly principal and interest payment from a recent statement, plus the next payment date. The calculator runs the loan month by month and shows the date of the final payment on your current payment.
What is the difference between this and a payoff quote?
This page projects a plan over time. A payoff quote from your servicer is the exact amount needed to close the loan on one date, including interest accrued to that day and any fees. Use the quote when you actually pay the loan off.
How much extra do I need to pay off my mortgage in 15 years?
Choose the target option and enter 15 years. For a $250,000 balance at 6.5% the payment needed is $2,177.77, so with a $1,800 payment the extra is $377.77. Your own balance and rate will give different figures.
Why does the payment I entered get rejected?
If the payment is no larger than one month of interest, the balance never falls. On $250,000 at 6.5%, a month of interest is $1,354.17. Use the principal and interest payment from your statement, not a number below the interest.
Does a one-time payment lower my next payment?
No. A one-time payment shortens the loan and cuts interest, but your required monthly payment stays the same. If you want a lower required payment after a large payment, ask your servicer about a recast.
What does the extra amounts table show?
It repeats the calculation for $100, $250, $500 and $1,000 more each month, plus your own amount, using the same balance and any one-time payment. Each row shows the final payment date, the payments left and the interest saved.