When to use this calculator
Estimate a future balance with a fixed rate and regular compounding. Assumes a constant nominal rate, no withdrawals and no additional deposits. Excludes fees and tax.
Explore the savings & interest calculators for other questions in this topic. For a related calculation, use the Continuous Compounding Calculator: Estimate a balance when nominal interest compounds continuously.
Compounding frequency is separate from deposits
A compounding frequency of 12 means interest is credited monthly; it does not mean you deposit money each month. This tool grows one initial amount. Use the monthly-deposits calculator when you also make regular contributions. Rates are assumptions, not promised returns.
PUTTING IT INTO PRACTICE
Compound Interest: 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 |
|---|---|
| Starting principal | 1,000 |
| Annual nominal rate (%) | 5 |
| Compounds per year (integer) | 12 |
| Years | 10 |
| Result | 1,647.009498 currency units |
- Check the input labels and enter the example values above.
- Apply the relationship: Balance = P(1 + r/(100n))^(nt).
- The result is 1,647.009498 currency units, rounded for display.
How to interpret your result
Assumes a constant nominal rate, no withdrawals and no additional deposits. Excludes fees and tax.
Match the quoted rate to its compounding convention. A nominal rate, effective annual rate and continuous rate are not interchangeable. Contribution timing also matters when interest is included in a future-value model.
Frequently asked questions
Does the result account for inflation or tax?
No. It is a nominal balance under the entered constant rate. Inflation affects purchasing power, and fees or taxes may reduce the amount retained.
Is a future savings value a forecast?
It is a scenario based on your entered rate and contributions. Changing rates, fees, tax or interrupted payments can change the actual outcome.
How do I use the compound interest calculator?
Enter starting principal, annual nominal rate (%), compounds per year (integer), years. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Balance = P(1 + r/(100n))^(nt).
What should I check before using the result?
Assumes a constant nominal rate, no withdrawals and no additional deposits. Excludes fees and tax.
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.
Further reading
For background on this topic, see OpenStax: compound interest ↗. This is a topic reference, not an external review or endorsement of this tool.
Calculators Map editorial process · Updated · Methods and limitations