Pay off your house sooner.

Free calculators that show how much interest you'll save. No signup, no ads on results.

5
calculators
$0
to use

Mortgage Payoff

Loan details

One-time lump sum

Results

Remaining balance over time

    Cumulative interest paid

    About PayoffNerd

    PayoffNerd is a free set of mortgage and loan calculators built for homeowners who want clarity — not a sales pitch.

    Your numbers stay with you

    Every calculation runs in your browser. We never see your loan balance, your rate, or anything else you enter.

    Instant results

    Every calculator updates in real time as you type. No "calculate" button, no page reloads, no waiting.

    Honest math

    Standard amortization formulas, with every assumption shown as an input you can change. Results include the total interest over the life of the loan.

    PayoffNerd is completely free to use. Results are estimates for informational purposes only — consult a licensed financial advisor or lender for personalized guidance.

    Frequently asked questions

    Answers to common questions about mortgages, extra payments, and how to use these tools.

    How much do extra mortgage payments actually save?

    It depends on your loan balance, rate, and how early in the term you start. On a $300,000 loan at 6.75% with 25 years left, adding just $200/month extra saves about $72,000 in interest and cuts roughly 4 years 10 months off your loan. With 30 years left, the same $200 saves about $110,000 and 7 years. Use the Mortgage Payoff calculator to model your exact situation.

    Should I pay extra on my mortgage or invest the money?

    If your mortgage rate is above ~5–6%, paying it down is often a guaranteed "return" that's hard to beat after tax. If your rate is lower, investing the difference in a diversified portfolio may come out ahead over a long horizon — but with more risk. To compare, use the Mortgage Payoff calculator to see what your extra payments would save, then weigh that against the return you realistically expect from investing.

    What's the difference between a HELOC and a cash-out refinance?

    A HELOC is a revolving credit line secured by your home — you keep your existing mortgage and add a second loan. A cash-out refi replaces your entire mortgage with a new, larger loan and gives you the difference in cash. If you have a low existing rate, a HELOC usually preserves it better. Use the HELOC vs Refi calculator to compare your specific numbers.

    Why does so much of my early payment go to interest?

    Mortgages use simple interest amortization — your payment each month is applied to interest first, then principal. Early in the loan, the balance is highest, so interest charges are highest. This flips over time. The Amortization calculator shows the exact split year by year.

    Is it better to make biweekly payments?

    Biweekly payments result in 26 half-payments per year, which equals 13 full payments instead of 12 — effectively one extra payment annually. You can model this by entering your monthly payment ÷ 12 as an extra monthly payment in the Mortgage Payoff calculator.

    Does renting ever make more financial sense than buying?

    Yes — especially if you plan to move within 3–5 years (buying costs like closing fees and agent commissions take time to recoup), or if your local market has high price-to-rent ratios. The Rent vs Buy calculator lets you try different time horizons and investment returns. It leaves out closing and selling costs, so in real life the break-even point comes later than it shows.

    Are these calculators accurate?

    They use standard financial formulas and are accurate for fixed-rate, fully amortizing loans. They don't account for PMI, HOA fees, tax deductions, or variable rate adjustments. Rent vs Buy includes property tax and maintenance but not insurance, closing costs or selling costs. Always verify results with your actual lender statements.

    How do I use a lump sum payment strategically?

    Lump sums applied early in the loan save the most interest because they reduce the principal that interest is calculated on for the longest period. A $10,000 payment in year 1 saves significantly more than the same payment in year 20. Use the lump sum field in the Mortgage Payoff calculator to see the impact.