Simple interest calculator
Enter the principal, annual rate, and time to get the interest and total amount. Uses SI = P × R × T ÷ 100, all in your browser.
Quick answer
Simple interest = principal × rate × time ÷ 100, where rate is the annual percent and time is in years. For example, 10,000 at 5% for 3 years earns 1,500 interest and totals 11,500.
Interest
1,500
Total amount
11,500
Not financial advice. A mathematical illustration only — real products may compound or add fees. Confirm figures with your institution.
Not financial or tax advice. Figures are mathematical illustrations only. Real products add fees, taxes, and terms that change the result — confirm with your bank, CA, or official notice. Numbers are not uploaded to our servers for processing.
Frequently asked questions
What is the simple interest formula?
Simple interest = principal × rate × time ÷ 100, where rate is the annual percentage and time is in years. For example, 10,000 at 5% for 3 years earns 10,000 × 5 × 3 ÷ 100 = 1,500.
How is simple interest different from compound interest?
Simple interest is charged only on the original principal, so it grows linearly. Compound interest is charged on principal plus accumulated interest, so it grows faster. Use the compound interest calculator to compare.
Can I use months instead of years?
Yes — enter the time in years as a decimal. Six months is 0.5 years; 18 months is 1.5 years.
Is my data uploaded?
No. TryCalculatingNow calculates in your browser. Your numbers are not uploaded to our servers for processing.