Simple Interest Calculator
Quickly calculate simple interest and the total amount using principal, annual rate and time period.
About Simple Interest
Simple interest is calculated only on the original principal: Interest = Principal × Rate × Time (rate in % per year, time in years). This tool also supports time entered in months.
When to use
- Short-term loans or deposits with non-compounding interest.
- Quick estimates for interest owed or earned.
- Education and budgeting examples.
Tip: For compounded interest use a compound interest calculator.
What Is Simple Interest?
Simple Interest is a quick and easy way to calculate how much extra money you will earn or owe over time on a fixed principal amount. It is commonly used in short-term loans, savings accounts, and financial planning. Simple interest grows at a steady rate, which makes it predictable and easy to manage.
Our Simple Interest Calculator helps you find out the total interest and final amount based on three key inputs — the principal amount, interest rate, and time period.
How to Use the Simple Interest Calculator
To calculate simple interest, just enter:
- Principal amount (P) – the initial amount of money borrowed or invested.
- Rate of interest (R) – the annual interest rate (percentage).
- Time (T) – the number of years or months the money is borrowed or invested for.
Once you enter these values, the calculator instantly shows:
- Simple Interest (SI) = (P × R × T) / 100
- Total Amount (A) = P + SI
This formula gives you the total cost of a loan or the total earnings on an investment.
Why Use the Simple Interest Calculator?
The Simple Interest Calculator saves time and ensures accuracy. Whether you’re a student learning basic finance, a borrower checking loan costs, or an investor estimating returns, this tool gives quick, reliable results. It eliminates manual math errors and provides instant clarity.
Benefits include:
- Fast and accurate calculations
- Easy comparison between different interest rates or time periods
- Clear understanding of how much you’ll pay or earn
Example
If you invest $1,000 at 5% interest for 3 years, the simple interest will be:
SI = (1000 × 5 × 3) / 100 = $150
Total amount = $1,150
Conclusion
Our Simple Interest Calculator is an essential tool for understanding basic financial growth. It helps you plan better, make smarter decisions, and manage your money effectively — all in just a few clicks.