What is Simple Interest?
Simple interest is calculated only on the original principal. The formula is Principal x Rate x Time. For example, $10,000 at 5% simple interest for 3 years yields $1,500 in total interest ($500 per year). Unlike compound interest, the interest earned each period remains constant.
Where Simple Interest Applies
Simple interest is commonly used in short-term loans, car loans, and some bonds. Treasury bills and commercial paper often use simple interest calculations. Understanding the difference matters: $10,000 at 5% for 10 years yields $5,000 with simple interest but $6,289 with compound interest - a 25% difference.
Key Considerations
When comparing financial products, always check whether the quoted rate uses simple or compound interest. A 5% simple interest rate is less valuable than a 5% compound rate over any period longer than one year. Most modern savings accounts and investment products use compound interest.