Free Extra Payment Calculator

See how making extra monthly payments on your mortgage reduces the total interest and shortens the payoff time.

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USD
%
years
USD

Months Saved

113

Total Interest Saved$151,522
New Payoff Time (months)247
Base Monthly Payment$1,995.91
Total Monthly (with extra)$2,295.91
Original Total Interest$418,527

Months Saved vs Loan Term

View formula & how it works →

Impact of Extra Mortgage Payments

Extra payments applied to principal reduce the balance faster, saving interest and shortening the loan term.

New Payoff Formula

New Months = log(PMT / (PMT - P x r)) / log(1 + r)

Where PMT is the total monthly payment (base + extra), P is the loan balance, and r is the monthly rate.

Why Extra Payments Are So Effective

  • Early in a mortgage, most of each payment goes to interest
  • Extra principal reduces the balance that accrues interest
  • The effect compounds: less interest means more of future payments go to principal
  • Even small extra amounts make a significant difference over decades

    • Strategies

  • Round up to the nearest hundred
  • Apply annual bonuses or tax refunds
  • Match extra payments to raises or eliminated expenses

    • Example Calculation

    A $300,000 loan at 7% for 30 years with an extra $300/month.

    1. 01Base payment: $1,995.91
    2. 02Total payment with extra: $1,995.91 + $300 = $2,295.91
    3. 03Original payoff: 360 months (30 years)
    4. 04New payoff: approximately 263 months (about 22 years)
    5. 05Months saved: 360 - 263 = 97 months (about 8 years)
    6. 06Original total interest: $418,528
    7. 07New total interest: approximately $303,726
    8. 08Interest saved: approximately $114,802

    Frequently Asked Questions

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