Interest Calculator
Calculate simple or compound interest for loans or investments. Input principal, rate, time, and compounding frequency to see total interest and final amount.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Interest Calculator
Follow these steps to calculate interest and final amount:
- Enter Principal Amount – Input the initial sum of money (e.g., $10,000). Use positive numbers.
- Enter Annual Interest Rate – Provide the yearly rate as a percentage (e.g., 5 for 5%).
- Enter Time Period – Specify the duration in years (e.g., 10). Decimals are allowed.
- Select Interest Type – Choose Simple Interest or Compound Interest from the dropdown.
- If Compound Interest – Select the Compounding Frequency (e.g., Monthly, Annually).
- Click "Calculate" – View the Total Interest earned and the Final Amount (principal + interest).
Note: All monetary values are in dollars ($). Ensure inputs are non-negative numbers. The formula used is displayed below the results for reference.
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Frequently Asked Questions
Simple interest is calculated only on the principal amount, while compound interest is calculated on the principal plus accumulated interest.
Select how often interest is added to the principal: annually, semi-annually, quarterly, monthly, or daily.
Yes, it works for both loans and investments. For loans, the interest is the cost of borrowing.
