🧮 Debt-to-Income Ratio Calculator
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Loan Payoff Calculator
Use this free loan payoff calculator to see when you can become debt-free and how much interest you can save with extra payments. It is built for searches like loan payoff calculator, debt payoff calculator, and extra payment calculator.
Interactive calculator
$
% / yr
$
$
Payoff Time
5 yr 2 mo
Total Interest
$5,511
Total Paid
$30,511
Extra Payment
+$100/mo
With extra payment:
New Payoff Time
4 yr 1 mo
Time Saved
1 yr 1 mo
earlier
Interest Saved
$1,126
New Total Interest
$4,386
How the math works
Formula
Months = −ln(1 − r × B / P) / ln(1 + r)
- BCurrent loan balance
- PMonthly payment amount
- rMonthly interest rate (annual rate ÷ 12)
- lnNatural logarithm
Plain English
Every extra dollar paid toward principal today eliminates future interest on that dollar for the entire remaining loan life. Adding $100/month to a $20,000 car loan at 6% cuts the payoff time from 60 months to roughly 47 and saves over $700 in interest. The earlier in the loan, the bigger the impact.
How to use this calculator
- 1
Enter the current balance, annual interest rate, regular monthly payment, and any extra payment.
- 2
Review the standard payoff timeline and total interest cost.
- 3
Compare the accelerated payoff results to see the time saved and interest saved.
Why this number matters
Debt payoff speed affects your cash flow, net worth, and financial flexibility. Even small extra principal payments can shorten the repayment period and cut interest cost dramatically, especially early in the life of a loan.
What this calculator helps you answer
- •How long will it take to pay off my loan at the current payment?
- •How much interest can I save by paying an extra $100 per month?
- •Is my payment high enough to actually reduce the balance each month?
Frequently asked questions
Why does the calculator warn that the payment does not cover interest?+
If your payment is too low, interest accrues faster than principal is repaid. In that case the balance can stagnate or grow instead of shrinking.
Do extra payments always go to principal?+
That depends on your lender and loan terms. In many cases extra payments reduce principal, but you should confirm how your loan servicer applies overpayments.
Should I pay off debt faster or invest instead?+
That depends on the interest rate, your liquidity needs, risk tolerance, and alternative return opportunities. This calculator helps quantify the guaranteed savings from faster repayment.
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Turn the calculator into an ongoing system
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