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Extra Mortgage Payment Calculator

See how extra mortgage payments cut interest and shorten your loan: interest saved, time saved, payoff date, and a balance chart.

Results update instantly.Change any value and the estimate recalculates on the spot.

Money

Extra Mortgage Payment Calculator

See how extra principal payments shrink your mortgage: interest saved, time saved, and your new payoff date.

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%
yrs
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Interest saved

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  • Time saved-
  • New payoff date-
  • Total interest without extra-
  • Total interest with extra-
Balance without extraBalance with extra

Estimate for planning only. Assumes a fixed rate, on-time monthly payments, and that extra payments go straight to principal. Actual savings vary with your loan terms. Not financial advice.

How to use this calculator

1. Enter your current loan balance, interest rate, and remaining term. 2. Add a monthly extra payment, a one-time lump sum, or both. 3. Read the interest and time saved, your new payoff date, and compare the two balance lines on the chart.

Worked example

A $300,000 balance at 6.5% with 30 years left, plus $200 extra per month: you save about $103,449 in interest, finish 6 years and 11 months early, and pay off in Nov 2049 instead of Oct 2056. Total interest drops from about $382,633 to about $279,185.

How the math works

Each month, interest accrues on the remaining balance, then your regular payment plus any extra goes toward principal. Extra payments shrink the balance faster, so less interest accrues and the loan ends early. Interest saved is the total interest on the original schedule minus the total interest with extra payments.

Do extra payments really save that much?
Yes. Every extra dollar goes straight to principal, so it stops accruing interest for the rest of the loan. On a large, long-term loan, even $100 to $200 a month can cut years off the term and tens of thousands in interest.
Should I make extra payments or invest instead?
Compare your mortgage rate with the return you expect from investing. If you can reliably earn more after taxes than your mortgage rate, investing usually wins on paper; if you value being debt-free, extra payments are a guaranteed return.
Is there a penalty for paying a mortgage early?
Most modern US mortgages have no prepayment penalty, but a few loans do. Check your loan documents or ask your servicer before sending extra principal.
Do extra payments lower my monthly payment?
No. Extra principal payments shorten the loan; they do not lower the required monthly payment. To lower the payment you need to refinance or recast the loan.

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How it works

How the Extra Mortgage Payment Calculator works

Quick answer: Adding $200 a month to a $300,000, 30-year mortgage at 6.5% saves about $103,449 in interest and pays the loan off 6 yrs 11 mos sooner.

Formula

Each month: interest = balance × rate ÷ 12
Principal paid = regular payment − interest + extra payment

The regular payment stays the same; every extra dollar goes straight to principal.

Worked example

$300,000 balance, 6.5%, 30 years remaining, $200 extra each month. Interest without extra: $382,633. With extra: $279,185. Saved: $103,449. Time saved: 6 yrs 11 mos.

$300,000 at 6.5%, 30 years remaining

Extra per monthInterest savedTime saved
$50$33,5822 yrs 2 mosOpen
$100$60,9954 yrs 0 mosOpen
$200$103,4496 yrs 11 mosOpen
$500$179,75912 yrs 6 mosOpen
$1,000$241,16217 yrs 3 mosOpen

Assumptions and limits

  • Check that your lender applies extra payments to principal and has no prepayment penalty.

Frequently asked questions

How do extra mortgage payments save interest?

Every extra dollar goes straight to principal, so it stops accruing interest for the rest of the loan. On a large, long-term loan, even $100 to $200 a month can cut years off the term and tens of thousands in interest.

Should I make extra payments or invest instead?

Compare your mortgage rate with the return you expect from investing. If you can reliably earn more after taxes than your mortgage rate, investing usually wins on paper; if you value being debt-free, extra payments are a guaranteed return.

Is there a penalty for paying a mortgage early?

Most modern US mortgages have no prepayment penalty, but a few loans do. Check your loan documents or ask your servicer before sending extra principal.

Do extra payments lower my monthly payment?

No. Extra principal payments shorten the loan; they do not lower the required monthly payment. To lower the payment you need to refinance or recast the loan.

Is it better to pay extra on the mortgage or invest?

Paying extra earns a guaranteed return equal to your mortgage rate. Investing may earn more but with risk; many people do both.

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