Simple Interest Calculator

Calculate simple interest and the total amount earned or owed using the principal, interest rate, and time period.

Calculate simple interest

Enter the principal amount, annual interest rate, and time period to calculate the simple interest and total amount.

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Tick this box only if you want to see the principal, interest, and total converted into another currency.
Currency conversion
The same exchange rate is applied to the principal, simple interest, and total amount.
Calculating…
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Converted amounts
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Annual interest rate —
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Step-by-step

How simple interest is calculated

Simple interest is calculated only on the original principal amount. Unlike compound interest, previously earned interest is not added to the principal for future interest calculations.

Simple Interest = P × R × T

Total Amount = P + Simple Interest

P = Principal   |   R = Annual Interest Rate   |   T = Time in Years

Step-by-step calculation

1
Enter the principal Enter the original amount of money invested, borrowed, or deposited.
2
Enter the annual interest rate Enter the annual simple interest rate as a percentage.
3
Enter the time period Enter the duration in years or months. Months are converted into years for the formula.
4
Calculate the interest The calculator multiplies principal, annual rate, and time to determine simple interest.
5
Calculate the total amount The original principal is added to the simple interest.

Simple interest example

Suppose you invest $10,000 at an annual simple interest rate of 5% for 3 years.

Principal $10,000.00
Annual interest rate 5%
Time 3 years
Simple interest $1,500.00
Total amount $11,500.00

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Important: This calculator uses the standard simple interest formula and is intended for general informational purposes. Actual financial products may use different interest calculations, fees, compounding schedules, payment terms, or other conditions. Currency conversion is optional and provided for informational purposes.