When to use this calculator
Estimate whole months to clear a balance with a fixed monthly payment. Payment must exceed monthly interest. Assumes no new borrowing, fees or rate changes.
Explore the loan & repayment calculators for other questions in this topic. For a related calculation, use the Debt Snowball vs Avalanche Calculator: Compare payoff time and interest for multiple debts using snowball and avalanche repayment strategies.
PUTTING IT INTO PRACTICE
Debt Payoff Time: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Balance | 1,200 |
| Fixed monthly payment | 100 |
| Nominal annual rate (%) | 0 |
| Result | 12 months |
- Check the input labels and enter the example values above.
- Apply the relationship: Months = −ln(1 − monthly rate × balance/payment)/ln(1+monthly rate).
- The result is 12 months, rounded for display.
How to interpret your result
Payment must exceed monthly interest. Assumes no new borrowing, fees or rate changes.
Use a fixed-rate amortising model for loans repaid by equal monthly instalments. An interest-only payment leaves the principal outstanding. Fees and contractual APR calculations require more than the interest rate alone.
Frequently asked questions
Does a lower monthly payment mean a cheaper loan?
Not necessarily. Extending the term can lower payments while increasing total interest. Compare both monthly affordability and overall cost.
When is the debt payoff time calculator useful?
Estimate whole months to clear a balance with a fixed monthly payment. Payment must exceed monthly interest. Assumes no new borrowing, fees or rate changes.
How do I use the debt payoff time calculator?
Enter balance, fixed monthly payment, nominal annual rate (%). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Months = −ln(1 − monthly rate × balance/payment)/ln(1+monthly rate).
What should I check before using the result?
Payment must exceed monthly interest. Assumes no new borrowing, fees or rate changes.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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