Simple Interest Calculator
Calculate simple interest instantly. Enter principal, rate, and time to see interest earned and total amount in real time.
Enter Details
Formula
SI = (P × R × T) ÷ 100
P = Principal · R = Rate · T = Time
Result
Total Amount
After 1 year
Simple Interest Calculator – Calculate SI Online
Our free simple interest calculator lets you calculate SI online in seconds. Whether you are planning a savings deposit, estimating loan interest, or learning the SI formula for exams — this tool gives you instant, accurate results. Just enter the principal amount, annual interest rate, and time period.
What is Simple Interest?
Simple Interest (SI) is a method of calculating interest on a principal amount where the interest is earned only on the original principal — not on previously accumulated interest. It is the most straightforward form of interest calculation and is commonly used in short-term loans, fixed deposits, vehicle loans, and school-level finance problems in India.
Unlike compound interest, simple interest does not compound over time. This makes it easier to understand and calculate, and it is often used in situations where the loan tenure is short.
Formula of Simple Interest
- P — Principal (the original amount deposited or borrowed)
- R — Rate of interest per annum (%)
- T — Time period in years
The total amount at maturity is: A = P + SI
Example Calculation
Suppose you deposit ₹10,000 in a bank at an annual interest rate of 5% for 2 years:
SI = (10,000 × 5 × 2) ÷ 100
SI = 1,00,000 ÷ 100
SI = ₹1,000
Total Amount = ₹10,000 + ₹1,000 = ₹11,000
You earn ₹1,000 as interest over 2 years, and the total maturity amount is ₹11,000.
Uses of Simple Interest in India
Personal & Vehicle Loans
Many short-term personal loans and vehicle loans in India use simple interest to calculate monthly repayments.
Fixed Deposits & Savings
Short-duration fixed deposits and recurring deposits often pay simple interest on the deposited amount.
Education Finance
Simple interest is a core topic in school and college mathematics in India — Class 7 to Class 10 NCERT syllabus.
Business Loans
Some microfinance and MSME loans use simple interest calculation, making repayment straightforward for small businesses.
Simple Interest vs Compound Interest
Simple Interest
- Interest on principal only
- Same interest every year
- Easy to calculate
- Lower total interest
Compound Interest
- Interest on principal + interest
- Grows faster over time
- More complex formula
- Higher total interest