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Mortgage Payoff Calculator

See how extra payments can help you pay off your mortgage faster and save thousands in interest.

By Drew Budwin · Last updated July 2026 · Methodology

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How We Calculate This

How Extra Payments Accelerate Your Payoff

Every dollar you pay above the scheduled amount goes straight to principal. Because interest is charged on the remaining balance, cutting the balance early means less interest accrues for the rest of the loan. This calculator amortizes your loan twice, once at the scheduled payment and once with your extra payment, then reports the difference in payoff date and total interest.

On a $300,000 loan at 6.5% over 30 years, adding $200 a month pays it off about 7 years early and saves more than $80,000 in interest. The earlier in the loan you start, the bigger the saving, because that is when the balance (and the interest on it) is highest.

Biweekly Payments and Accelerated Payoff Plans

A biweekly plan pays half your monthly amount every two weeks. Because there are 52 weeks in a year, you make 26 half-payments, which equals 13 full monthly payments instead of 12, one extra payment a year. To model that here, divide one monthly payment by 12 and enter it as your extra monthly payment. It is the same acceleration a mortgage-accelerator program sells, without any fee.

Mortgage Payoff Calculator Formula

This calculator uses the standard mortgage amortization formula to compute your monthly payment:

M = P × [r(1+r)^n] / [(1+r)^n - 1]

where P is the principal, r is the monthly interest rate, and n is the total number of payments. Each extra dollar you pay goes directly to reducing your principal, creating a compounding effect that accelerates your payoff.

How to Use This Calculator

  1. Enter your remaining Loan Amount.
  2. Enter your Annual Interest Rate.
  3. Enter your Loan Term in years.
  4. Enter any Extra Monthly Payment you plan to make (enter 0 if none).
  5. Click Calculate to see how much time and interest you save.

Frequently Asked Questions

How much can I save by making extra mortgage payments?

Even small extra payments can save you tens of thousands of dollars in interest over the life of your loan. For example, adding $200 per month to a $300,000 mortgage at 6.5% can save you over $80,000 in interest and cut more than 7 years off your loan.

Is it better to make extra payments or invest the money?

It depends on your interest rate and expected investment returns. If your mortgage rate is higher than what you expect to earn from investments (after taxes), paying down the mortgage may be the better choice. The guaranteed return from paying off debt equals your interest rate. You can model potential investment growth with the compound interest calculator to compare.

Should I refinance or make extra payments?

Refinancing lowers your interest rate but typically involves closing costs. Extra payments reduce your principal without any fees. Consider refinancing if you can get a significantly lower rate, and use extra payments alongside your current or new mortgage to accelerate payoff further.

Does my lender apply extra payments to principal automatically?

Not always. Some lenders apply extra payments to future scheduled payments instead of the principal. Contact your lender to ensure extra payments are applied directly to the principal balance, or specify 'apply to principal' when making payments.

Are there any penalties for paying off my mortgage early?

Some mortgages include prepayment penalties, though these have become less common. Check your loan agreement or ask your lender. Most conventional mortgages originated after 2014 do not have prepayment penalties due to regulations under the Dodd-Frank Act.

Is it better to make one lump-sum payment or increase monthly payments?

Both strategies reduce interest, but a lump sum applied early in the loan saves more because it immediately reduces the principal that accrues interest. If you do not have a lump sum available, consistently higher monthly payments achieve a similar effect over time.

How do biweekly mortgage payments help me pay off faster?

Paying half your monthly amount every two weeks results in 26 half-payments a year, which equals 13 full monthly payments instead of 12. That one extra payment each year goes entirely to principal and can shave years off a 30-year loan. To model it here, enter one-twelfth of your monthly payment as the extra monthly payment.

Are mortgage accelerator programs worth it?

Usually not. Most accelerator programs and biweekly-payment services charge a setup or per-transaction fee to do something you can do for free: send extra money toward principal. Enter that extra amount above and you get the same faster payoff without paying anyone.

Further Reading

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