Why use this calculator
Simple interest calculations are used for short-term loans, certificates of deposit, and basic financial planning. Unlike compound interest, simple interest is calculated only on the original principal, making it straightforward to understand and predict.
How to use it
Enter your principal amount, annual interest rate, and time period. The calculator instantly shows total interest earned and the final amount.
The formula
I = P × r × t, where I is interest, P is principal, r is annual rate (as decimal), and t is time in years. Total = P + I.
Worked examples
$5,000 at 5% for 3 years
$750 interest earned, total of $5,750
$10,000 at 8% for 1 year
$800 interest earned
When people use it
- Short-term loan calculations
- CD (Certificate of Deposit) returns
- Understanding basic interest concepts
Tips
- Simple interest is less favorable for savings but better for borrowers compared to compound interest
- Always compare APR vs APY when evaluating financial products
Questions people ask
- When is simple interest used?
- Simple interest is commonly used for short-term loans, auto loans, and some bonds. Most savings accounts and long-term investments use compound interest instead.