Loan inputs
Enter the original loan details, current loan position, and any extra payment strategy. After you submit, the results appear above this form.
Example data table
This worked example shows how extra monthly payments and one lump sum can shorten a personal loan payoff timeline.
| Scenario | Original Loan | APR | Term | Payments Made | Estimated Balance | Extra Monthly | Lump Sum | Months Saved | Interest Saved |
|---|---|---|---|---|---|---|---|---|---|
| Sample strategy | $25,000.00 | 10.5% | 60 months | 18 | $18,818.15 | $150.00 | $1,000.00 in month 6 | 12 | $1,205.24 |
Formula used
The calculator uses standard amortization math, then rebuilds the remaining schedule with your extra payment strategy.
1) Standard monthly payment
Payment = P × r ÷ (1 − (1 + r)−n)
Here, P is original principal, r is monthly interest rate, and n is the original number of monthly payments.
2) Estimated remaining balance
Balance after k payments = P(1 + r)k − Payment × [((1 + r)k − 1) ÷ r]
If you enter a current balance override, that value replaces the estimated balance for all payoff comparisons.
3) Early payoff simulation
New payment each month = Standard payment + Extra monthly payment
The calculator adds optional lump sums in the chosen month, updates interest on the remaining balance, and repeats until the loan reaches zero.
4) Savings measures
Months saved = Baseline remaining months − Accelerated remaining months
Interest saved = Baseline remaining interest − (Accelerated interest + penalty)
How to use this calculator
- Enter the original loan amount, interest rate, and original repayment term.
- Add how many payments you have already made. If you know the lender’s exact balance, enter it as a balance override.
- Choose your early payoff strategy, such as an extra monthly payment, a future lump sum, or a prepayment penalty amount.
- Optionally enter a target payoff period to see the payment needed to clear the loan within that timeframe.
- Press Calculate early payoff. Review the summary, compare baseline and accelerated results, then export the schedule as CSV or PDF.
Frequently asked questions
1) What does this calculator estimate?
It estimates your remaining balance, current standard payment, baseline payoff date, accelerated payoff date, months saved, interest saved, and a month-by-month payoff schedule.
2) Should I enter my current balance?
Yes, when you know the lender’s exact balance. That gives the most realistic result. If you leave it blank, the tool estimates the balance from the original loan details and payments made.
3) How is interest saved calculated?
The tool compares remaining interest under the baseline schedule against the accelerated schedule. If you enter a prepayment penalty, that fee is included before net savings are shown.
4) Can I test lump-sum payments?
Yes. Enter a one-time lump sum and the month when you plan to apply it. The calculator adds that amount after the regular payment in the selected month.
5) What if my loan has zero interest?
The calculator still works. It switches to a simple balance reduction method where the monthly payment equals principal divided by the number of months remaining.
6) What does the target payoff field do?
It estimates the monthly payment required to clear the current balance within your chosen number of months. This helps you test whether your early payoff goal is realistic.
7) Why might lender statements differ slightly?
Lenders may use daily interest, exact due dates, rounded payment allocations, escrow items, or fees not included here. This tool is excellent for planning, but statements remain the official source.
8) When is an early payoff strategy most useful?
It is most useful when your loan has a moderate or high interest rate, you can make steady extra payments, and any prepayment fees are small enough to preserve savings.