Short-term interest estimate
Enter a principal amount, annual rate, and time period to estimate interest without compounding.
Simple interest calculator
Estimated interest -
Final amount -
Principal -
Average monthly interest -
Months -
Annual rate -
Estimates are educational and use the simple interest formula without compounding, fees, taxes, or account rules.
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Formula check
Use the result to verify simple interest homework or a quick manual calculation.
Compare with compounding
Compare the final amount with a compound interest estimate to see the effect of compounding.
About this helper
This calculator uses the simple interest formula: interest equals principal times annual rate times time. It does not compound interest and does not include taxes, fees, inflation, payment schedules, or account-specific rules.
What is simple interest?
Simple interest is calculated only on the original principal, not on previously earned interest.
Are my amounts uploaded?
No. The calculation runs in your browser and the site does not receive the amounts you type.
Does this include compounding?
No. Use the compound interest calculator when interest earns more interest over time.
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