Loan Payoff Calculator: Time and Interest to Clear a Loan
See how long it takes to pay off a loan at a chosen monthly payment, and how much interest a larger payment would save.
Adjust the inputs and select Calculate for a full breakdown.
Year-by-year payoff schedule
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Time to pay off | Total interest | Total paid |
|---|---|---|---|
| $18k · 9% · $450/mo | 4 years | $3,480.98 | $21,480.98 |
| $6k · 11% · $250/mo | 2y 4m | $807.43 | $6,807.43 |
| $40k · 8% · $800/mo | 5y 2m | $8,817.88 | $48,817.88 |
| $12k · 13% · $500/mo | 2y 4m | $1,972.44 | $13,972.44 |
How This Calculator Works
Enter the remaining loan balance, its interest rate, and the monthly payment you plan to make. The calculator works month by month — adding interest, subtracting the payment — until the balance clears, then reports the payoff time and total interest. Raise the payment to see the effect of overpaying.
The Formula
Debt Payoff Time
B = balance, P = fixed monthly payment, r = monthly rate (APR ÷ 12), n = months to clear
Worked Example
An $18,000 loan balance at 9% paid at $450 a month is cleared in 48 months. Interest across those four years totals about $3,481, bringing the full cost of clearing the balance to roughly $21,481.
Key Insight
Paying more than the scheduled amount attacks the principal directly, and on an installment loan that compounds in your favor: a smaller balance accrues less interest every month that follows, so modest overpayments snowball into real savings.
Frequently Asked Questions
Does overpaying a loan always help?
Usually, but check for prepayment penalties. Some loans charge a fee for early payoff; where there is none, extra principal payments reliably cut total interest.
What balance should I enter?
Enter the current outstanding balance, not the original loan amount. The payoff time is measured from where the loan stands today.
How is this different from an amortization calculator?
An amortization calculator finds the required payment for a set term. This one does the reverse: you choose the payment, and it finds how long the loan takes to clear.
Will my lender apply extra to principal?
Confirm it. Some lenders apply overpayments to future installments instead of principal. To save interest, the extra must reduce the principal balance.
Does a lower rate change the payoff much?
Yes. A lower rate means less of each payment goes to interest, so the balance falls faster. Re-run the calculator if you refinance to a new rate.
Related Calculators
Data Sources & Benchmarks
This calculator draws on 3 independent, dated sources. The starting values for interest rate are taken from the benchmarks below and refresh whenever the snapshots are updated.
Methodology & Review
The payoff is simulated month by month from the current balance: interest is charged, the fixed payment is deducted, and months are counted until the balance clears. Prepayment penalties are not modeled.
Written by Ugo Candido · Last updated May 17, 2026.