Free calculators that show exactly how much interest you can save — with extra payments, lump sums, or refinancing. No signup, no ads on results.
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PayoffNerd is a free set of mortgage and loan calculators built for homeowners who want clarity — not a sales pitch.
All calculations run entirely in your browser. We never see your loan balance, rate, or any financial data you enter.
Every calculator updates in real time as you type. No "calculate" button, no page reloads, no waiting.
Standard amortization formulas, no hidden assumptions. Results show the full picture including total interest paid over the life of the loan.
PayoffNerd is ad-supported and completely free to use. Results are estimates for informational purposes only — consult a licensed financial advisor or lender for personalized guidance.
Answers to common questions about mortgages, extra payments, and how to use these tools.
It depends on your loan balance, rate, and how early in the term you start. On a $300,000 loan at 6.75%, adding just $200/month extra can save over $60,000 in interest and cut nearly 5 years off your loan. Use the Mortgage Payoff calculator to model your exact situation.
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. The Rent vs Buy calculator can help model the wealth comparison.
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.
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.
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.
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 model different time horizons and investment return assumptions.
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. Always verify results with your actual lender statements.
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.