Mortgage Payoff Calculator

This calculator shows how extra payments, biweekly payments, or a full payoff change the length of your mortgage and the total interest you pay. Enter your original loan details and remaining term, or just your current balance and monthly payment, choose a repayment strategy, and the calculator shows the new payoff date, how much time you save, and how much interest you avoid.

How principal and interest work

Every fixed-rate mortgage payment splits into two parts: interest on the remaining balance, and principal, the portion that reduces what you owe. Because interest is calculated on the outstanding balance, early payments are weighted heavily toward interest. On a $400,000 loan at 6.5% for 30 years, the first monthly payment of about $2,528 sends roughly $2,167 to interest and only $361 to principal. By year 25, that same payment flips: around $400 to interest and $2,128 to principal.

This front-loading matters because any extra amount you pay goes directly to principal. It eliminates the future interest that balance would have generated, which is why even a small regular addition can remove years from a mortgage.

Extra payments

Adding to your monthly payment is the most direct way to pay off a mortgage early. You can add a fixed amount each month, a lump sum once a year, or a one-time payment at any point. Each approach reduces the balance faster, and because interest accrues on the remaining balance, every dollar of principal paid early removes multiple future dollars of interest.

On a $300,000 loan at 6% for 30 years, the standard monthly payment is $1,799. Adding $200 per month from day one pays off the loan about 6 years and 2 months early, saving around $57,000 in interest. A single one-time payment of $10,000 in year two shortens the loan by about 14 months and saves roughly $25,000. The exact figures depend on your balance and rate, which is why this calculator runs a full month-by-month simulation rather than an approximation.

Biweekly payments

A biweekly payment plan involves paying half your normal monthly payment every two weeks instead of the full amount once a month. Because there are 52 weeks in a year, this produces 26 half-payments, equal to 13 full monthly payments rather than 12. That one extra payment per year accelerates payoff without requiring a large upfront commitment.

On a $300,000 loan at 6% for 30 years, switching to biweekly payments typically removes about 4 years and 6 months from the loan and saves roughly $45,000 in interest. The effect is smaller on shorter-term loans, since there are fewer remaining payments for the benefit to compound across. Some lenders offer biweekly programs formally; others require you to make the extra payment manually each year. Confirm with your servicer how they apply payments before choosing this approach.

Refinancing to a shorter term

Refinancing replaces your current mortgage with a new loan, often at a different rate or term. If rates have dropped since you took out your original loan, refinancing to a shorter term can cut both the rate and the repayment period at once.

For example, a borrower seven years into a 30-year mortgage at 7% with a $280,000 remaining balance might refinance to a 20-year fixed loan at 6%. The monthly payment would rise by about $150, but the total interest paid over the remaining life of the loan would fall by more than $60,000. Refinancing comes with closing costs, typically 2% to 5% of the loan amount. Calculate how long it takes for the interest savings to cover those costs before committing. If you plan to sell before that break-even point, refinancing probably does not make financial sense. For a full analysis, see our Refinance Calculator.

Prepayment penalties

Some mortgage contracts include a prepayment penalty, a fee charged if you pay off the loan earlier than scheduled. Lenders structure these penalties in different ways: a flat percentage of the remaining balance, several months of interest, or a sliding scale that shrinks each year.

Prepayment penalties have become less common in recent years, and most are limited to the first three to five years of the loan. After that period, the penalty clause typically expires. FHA loans, VA loans, and mortgages insured by federally chartered credit unions cannot include prepayment penalties. Read your loan agreement or ask your servicer before making a large extra payment, since the fee can exceed the interest savings early in the loan.

Opportunity cost

Extra mortgage payments reduce a relatively low-interest debt. That may not always be the highest-return use of the money. Credit card debt at 20% costs far more than a mortgage at 6.5%, so paying the cards first cuts your overall interest burden faster. Once high-interest debt is gone, extra mortgage payments compete against other options such as retirement accounts or taxable investments.

Over long periods, a diversified stock portfolio has historically returned around 8% to 10% annually, which is above most mortgage rates. Contributing to a 401(k) up to the employer match deserves priority since the match is an immediate 50% to 100% return. A Roth IRA or traditional IRA adds tax-sheltered space. Only after those accounts are funded does accelerating the mortgage become the clearest path for most borrowers. Most borrowers also need an emergency fund of three to six months of expenses before committing extra cash to an illiquid asset like a home.

Examples

Example 1: Lisa has $245,000 remaining on a 6% mortgage with 22 years left. She has no credit card debt and has maxed out her 401(k) contributions for the year. She decides to add $300 per month to her payment. The calculator shows she would pay off the mortgage about 7 years early and save roughly $62,000 in interest, ending with a clear title to her home well before retirement.

Example 2: James has $190,000 remaining on his mortgage at 5.8% with 18 years left. He also carries $14,000 in credit card debt at 22% interest. His financial advisor suggests paying the cards first. At 22%, that debt costs about $3,000 per year in interest alone. Eliminating it before adding extra mortgage payments saves more per dollar than accelerating the mortgage would.

Example 3: Maria is two years from retirement with $60,000 remaining on her mortgage and 5 years left on the term. She has a six-month emergency fund, no other debt, and fully funded retirement accounts. Her advisor recommends a lump-sum payoff. She enters her balance and current payment into the calculator above, confirms there is no prepayment penalty, and pays off the loan. She enters retirement with no housing debt and a lower monthly expense requirement.

Recasting, the option most borrowers have not heard of

Paying a lump sum against principal shortens the term and leaves the payment where it was. A recast does the opposite. You pay the lump sum, and the servicer re-amortizes the remaining balance over the remaining term, which lowers the monthly payment while keeping the same payoff date and the same interest rate.

That is the right tool when the goal is breathing room in the monthly budget rather than an early finish. Servicers who offer it usually charge a small administrative fee and require a minimum principal reduction. It is generally unavailable on FHA, VA and USDA loans, and it is not automatic on conventional loans either, so ask before sending the money.

Prepayment penalties are now rare, and limited

Federal rules have squeezed prepayment penalties out of most consumer mortgages. Under Regulation Z a penalty is allowed only on a fixed or step-rate qualified mortgage that is not higher-priced, it may run for no more than three years, and it is capped at 2% of the outstanding balance in the first two years and 1% in the third. The lender also has to offer a comparable loan without a penalty.

The practical answer for a loan written in the last decade is that there is probably no penalty at all, but the loan documents settle it. Look for a prepayment section in the note rather than relying on what you were told at closing.

Make sure the money lands where you think

An extra payment is not automatically applied to principal. Many servicers hold it as a prepaid regular payment, which advances the due date and does nothing for the balance. Some apply it to escrow. Send extra amounts as a separate transaction marked for principal only, then check the next statement to confirm the balance dropped by the full amount. This one detail decides whether the saving in the results above is real or imaginary.