When to use this calculator
Estimate a non-negative nominal annual loan rate from a level monthly payment. An inverse nominal-rate model, not a statutory APR calculation. Fees and irregular dates are excluded.
Explore the loan & repayment calculators for other questions in this topic. For a related calculation, use the Loan Total Interest Calculator: Estimate total interest on a fixed-rate monthly amortising loan.
PUTTING IT INTO PRACTICE
Loan Rate From Payment: 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 |
|---|---|
| Loan principal | 1,000 |
| Fixed monthly payment | 1,100 |
| Number of payments (integer) | 1 |
| Result | 120 nominal % per year |
- Check the input labels and enter the example values above.
- Apply the relationship: Solve monthly amortisation payment for the monthly rate, then multiply by 12..
- The result is 120 nominal % per year, rounded for display.
How to interpret your result
An inverse nominal-rate model, not a statutory APR calculation. Fees and irregular dates are excluded.
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 loan rate from payment calculator useful?
Estimate a non-negative nominal annual loan rate from a level monthly payment. An inverse nominal-rate model, not a statutory APR calculation. Fees and irregular dates are excluded.
How do I use the loan rate from payment calculator?
Enter loan principal, fixed monthly payment, number of payments (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Solve monthly amortisation payment for the monthly rate, then multiply by 12..
What should I check before using the result?
An inverse nominal-rate model, not a statutory APR calculation. Fees and irregular dates are excluded.
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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