Simple Interest Calculator
Calculate simple interest for any principal, rate, and time period.
Total Amount
₹1.35 L
SI = P × R × T ÷ 100
Principal
₹1.00 L
Interest
₹35.00 K
Total
₹1.35 L
Simple Interest Calculator visual insights
Future value
₹50.46 L
Growth
₹32.46 L
How to Use This Calculator
Enter Amount
Set your loan amount or investment using the slider or input field.
Set Rate & Tenure
Adjust the interest rate and time period to match your scenario.
Get Results
See your EMI, total interest, and full payment breakdown instantly.
Share & Plan
Share the result link or download the amortization schedule as PDF.
About Simple Interest Calculator
Simple Interest Calculator helps you estimate investment growth, required contribution, annualised return, and future corpus using India-focused assumptions and INR formatting. Calculate simple interest for any principal, rate, and time period.
This tool is useful for Indian investors planning SIPs, mutual funds, deposits, inflation-adjusted goals, and portfolio returns. It is designed for quick planning before comparing bank offers, investment options, tax choices, or scheme rules with a qualified professional.
The calculations are tailored for users in India and use Indian number formatting, rupee values, and locally relevant finance terms wherever applicable.
Results are estimates for education and planning. Final decisions should use official documents, lender statements, scheme rules, tax notices, or advice from a qualified professional.
Frequently Asked Questions
What is the simple interest formula?
SI = (P × R × T) / 100, where P is principal, R is the annual interest rate (%), and T is time in years. Total amount = P + SI. Simple interest grows linearly — unlike compound interest it does not earn interest on interest.
Where is simple interest used in India?
Simple interest is used for most personal loans, auto loans (for flat-rate schemes), some short-term money-lending arrangements, infrastructure bonds, and certain farm-credit products. Most bank FDs and EMI loans use compound or reducing-balance interest.
Simple vs compound interest — which is better?
As a borrower, simple interest is better — you pay less. As an investor, compound interest is better — you earn more. Over 20 years at 10%, ₹1 lakh becomes ₹3 lakh under SI vs ₹6.73 lakh under annual compounding.
Is simple interest the same as flat rate?
They are related but not identical. Flat-rate loans charge interest on the original principal throughout the tenure — that is simple interest. Reducing-balance loans charge interest on the outstanding balance each month — that approximates compound interest.
How do I convert flat rate to reducing-balance rate?
Roughly, effective reducing-rate ≈ flat rate × 1.8 to 2.0. A 10% flat rate loan is roughly equivalent to an 18-20% reducing-balance rate. Always compare loans on reducing-balance basis for apples-to-apples comparison.
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Methodology & Formulas
All formulas used here comply with RBI guidelines and standard Indian financial conventions. Calculators are updated for FY 2026–27.
Last updated: April 2026