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.
Avalanche vs snowball — debt payoff strategy
Two competing debt payoff strategies for multi-loan situations. (1) AVALANCHE — pay minimums on all debts; put extra payment on HIGHEST-INTEREST-RATE loan. Mathematically optimal — saves the most interest. (2) SNOWBALL — pay minimums on all; put extra on SMALLEST-BALANCE loan first. Less optimal mathematically but psychologically motivating — quick wins build momentum.
Research (Gal & McShane, Journal of Marketing Research 2012) suggests SNOWBALL produces higher debt-payoff completion rates despite higher interest cost. Borrowers who feel progress (debt eliminations) stick with the plan longer than those waiting years for the largest debt to disappear.
Optimal approach: SNOWBALL for borrowers needing motivation; AVALANCHE for disciplined borrowers focused on optimization. Both are vastly better than minimum-only payments. A borrower with $30K total debt at average 12% paying minimums takes ~30 years to pay off; either accelerated strategy clears debt in 3-5 years.
Where extra payments have most impact
Extra principal payments have greater impact early in the loan because interest charges are higher when balance is large. Year 1 of 30-year mortgage at 7%: ~95% of payment is interest, ~5% principal. Year 25: ~30% interest, ~70% principal. An extra $100/month in year 1 saves substantially more total interest than $100/month in year 25.
But borrowers should also consider opportunity cost. Extra mortgage payment at 7% saves 7% guaranteed. Investing same money in tax-advantaged retirement (401k match) provides immediate 100% return on matching portion plus long-term growth. Hierarchy: (1) max 401k match; (2) high-interest debt (15%+ credit cards); (3) emergency fund (3-6 months expenses); (4) maximize tax-advantaged retirement; (5) extra mortgage / student loan payment.
For low-rate fixed mortgages (3-4% from 2020-2021), early payoff is often suboptimal. Investing at higher expected return (S&P 7% historical real) outperforms locking in 3-4% guaranteed return. For high-rate loans (7%+ mortgage 2023+ origination), early payoff competes more favorably with investment alternatives.
Loan payoff acceleration — illustrative $30,000 loan at 7%
Reference impact of extra payments on $30,000 loan at 7% interest, 60-month term ($594 minimum payment).
| Extra payment/month | Payoff time | Total interest | Interest saved vs no extra |
|---|---|---|---|
| $0 | 60 months | $5,640 | $0 |
| $50 | 52 months | $4,830 | $810 |
| $100 | 47 months | $4,290 | $1,350 |
| $200 | 40 months | $3,360 | $2,280 |
| $300 | 34 months | $2,690 | $2,950 |
| $500 | 27 months | $1,950 | $3,690 |
Extra payment value scales non-linearly. $100/month extra saves $1,350 (per dollar extra: $13.50). $500/month saves $3,690 (per dollar extra: $7.38). Smaller consistent extras have higher per-dollar value than large extras. This is why even modest $50-$100/month additional payments compound to substantial 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.
When is this calculator unreliable?
For variable-rate loans (future rate changes affect actual payoff differently from projection), for loans with prepayment penalties (penalty can erase savings from early payoff — check loan documents), or when extra payments are sporadic vs consistent (large occasional payments produce different results than steady extras). For borrowers managing multiple debts, consider avalanche (high-rate first) vs snowball (small balance first) strategies.
References & Authoritative Sources
- Consumer Financial Protection Bureau (CFPB) — Prepayment Penalties Guidance · consulted June 1, 2026 · Federal consumer guidance on loan payoff
- Federal Reserve — Truth in Lending Act (Regulation Z) — Truth in Lending Disclosure Requirements · consulted June 1, 2026 · Federal lending disclosure requirements
- Investopedia — Loan Amortization — Loan Amortization Schedule · consulted June 1, 2026 · Standard amortization methodology
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
Generic loan payoff calculates months/years to pay off any fixed-rate amortizing loan with optional extra principal payments. Iterates monthly: interest = balance × monthly rate; principal = payment − interest + extra; new balance = balance − principal. The calculator returns payoff date and total interest. Applies to mortgages, auto loans, personal loans, student loans, business loans — any fixed-rate amortizing structure. Variable-rate loans require additional assumptions about future rate changes. RELIABILITY: Reliable for fixed-rate loans with no prepayment penalty. Less reliable for variable-rate loans (rate changes during payoff period affect outcome), loans with prepayment penalties (penalty can erase savings from early payoff), or when extra payments are sporadic vs consistent (calculator typically assumes consistent extra).
Updated