Simple Interest Calculator
Calculate simple interest, interest earned, and total maturity amount instantly.
Unlike compound interest where gains accumulate on previously earned returns, Simple Interest calculates linear accrual exclusively on the original initial principal ($SI = (P \times R \times T) / 100$). It is standard for short-term promissory notes, auto-debit penalty calculations, and informal lending agreements.
Simple Interest Calculator
Calculate simple interest, interest earned, and total maturity amount instantly.
Simple vs. Compound Growth Distortions
Linear Growth vs Exponential CompoundingOver a 20-year horizon on a ₹10 Lakh principal at 10% per annum, Simple Interest yields ₹20 Lakhs in total interest (₹30 Lakhs total), whereas Compound Interest generates ₹57.27 Lakhs in interest (₹67.27 Lakhs total) — demonstrating a ₹37.27 Lakh compounding advantage.
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How the Simple Interest Calculator Works
Follow these simple steps to get accurate results instantly.
Enter Principal Amount
Enter the amount of money invested or borrowed.
Enter Interest Rate
Enter the annual interest rate percentage.
Enter Time Period
Specify the duration in years.
View Results
See interest earned and total maturity amount.
Simple Interest Formula
SI = (P × R × T) ÷ 100
Simple Interest is calculated on the original principal amount for the entire investment or loan duration.
Example Calculation
Input: Principal: ₹1,00,000, Rate: 8%, Time: 5 Years
Output: Simple Interest = ₹40,000, Total Amount = ₹1,40,000
Common Uses
- • Loan Interest Calculation
- • Savings Interest Estimation
- • Educational Purposes
- • Financial Planning
- • Investment Analysis
Frequently Asked Questions
Verified answers to essential calculation and diagnostic questions.
Simple Interest is interest calculated only on the original principal amount throughout the investment or loan period.
Simple Interest is calculated using the formula SI = (Principal × Rate × Time) ÷ 100.
Simple Interest is calculated only on the principal amount, while Compound Interest is calculated on both principal and accumulated interest.
Simple Interest is commonly used for short-term loans, educational examples, and basic financial calculations.
Yes, it can estimate interest payable on loans that use simple interest calculations.
Written & maintained by Aditya Singh
Aditya Singh is a software engineer and the founder of DevCalc, based in Uttar Pradesh, India. He builds and maintains every calculator on this site, using standard, verified formulas — the same ones used by banks, institutions, and educators — with careful attention to accuracy. Read more about the author →
This calculator and its guidance are for general educational purposes only and do not constitute financial, investment, or tax advice. Verify figures with a qualified professional before making financial decisions.