What is simple interest?
Simple interest is the amount earned or charged on an original principal for a fixed period without compounding. It can help explain basic loan or savings terms but may differ from actual bank calculations.
Simple interest formula
I = P × R × T ÷ 100 where P is principal, R is annual interest rate (percent), and T is years. Total amount equals principal plus interest.
Worked example
For a $10,000 loan at 5% simple interest over three years, interest is $10,000 × 5 × 3 ÷ 100 = $1,500. Total amount before fees is $11,500.
Understanding results
The calculator shows the interest, combined principal and interest, and average monthly equivalent of the interest amount. It does not create a loan repayment schedule and the average monthly equivalent is not an EMI.
Simple versus compound interest
At annual compounding, $10,000 at 5% for three years grows to $11,576.25, compared with $11,500 under simple interest. The extra $76.25 reflects interest earned on prior interest.
Common mistakes
Use an annual percentage rate, not a decimal like 0.05 when the input expects 5. Convert six months to 0.5 years and remember real loans may include fees, changing rates or different accrual methods.
Further reading
Read Simple Interest Formula and Worked Examples for more formula examples and practical comparisons.