Simple Interest Calculator
Calculate simple interest and total amount using a principal amount, annual interest rate and time period.
Enter your values
Enter the principal, annual interest rate and time period.
Simple interest summary
Review the calculated interest, total amount and effective growth.
Enter your calculation details
DIXANI will calculate the simple interest and total amount.
Understand your result
See the principal, interest and resulting total amount separately.
What your simple interest results mean
The calculation separates the original principal from the interest earned or charged, making it easier to understand how the rate and time period affect the final amount.
Principal Amount
The principal is the original amount borrowed, invested or saved. Simple interest is calculated from this original amount throughout the selected period.
Simple Interest
This is the total interest calculated from the principal, annual interest rate and time period. Previously accumulated interest is not added to the calculation base.
Total Amount
The total amount combines the original principal with the calculated simple interest. It shows the estimated final value at the end of the selected period.
Growth Percentage
The growth percentage shows the total simple interest as a percentage of the original principal over the full period entered into the calculator.
Quick example: At 5% simple interest per year, USD 10,000 generates USD 500 of interest each year. Over three years, the total simple interest is USD 1,500.
Example simple interest calculation
Suppose you have a principal amount of USD 10,000 at an annual simple interest rate of 5% for 3 years.
Principal: USD 10,000 • Interest Rate: 5% • Time: 3 years
Simple Interest: USD 10,000 × 5% × 3 = USD 1,500
Total Amount: USD 10,000 + USD 1,500 = USD 11,500
Simple interest formula
Simple interest is calculated only on the original principal amount.
I = simple interest, P = principal, r = annual interest rate expressed as a decimal, and t = time in years.
The total amount is the original principal plus the calculated simple interest.
What's the difference?
Simple interest and compound interest calculate growth differently.
Simple Interest
Interest is calculated using the original principal throughout the entire period.
Compound Interest
Interest can earn additional interest because previously accumulated interest is added to the balance.
Time Period
For simple interest, the relationship between time and interest is linear when the rate remains constant.
Compare Both
Use DIXANI's Compound Interest Calculator when you need to include compounding or recurring contributions.
When is simple interest useful?
Simple interest calculations can be useful when interest is based only on the original principal.
Basic Loan Estimates
Estimate interest where a loan or agreement specifically uses simple interest.
Savings Estimates
Calculate basic growth when interest does not compound during the selected period.
Business Planning
Compare financing or investment scenarios using a straightforward interest assumption.
Education
Understand the relationship between principal, rate, time and interest.
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Open Calculator →Simple Interest Calculator — Frequently Asked Questions
What is simple interest?
Simple interest is interest calculated using only the original principal amount rather than adding previously earned interest to the calculation base.
How do you calculate simple interest?
Multiply the principal by the annual interest rate expressed as a decimal and by the time in years. The formula is I = P × r × t.
Can I enter the time in months?
Yes. Select Months and the calculator will convert the entered period into years for the simple interest calculation.
What is the difference between simple and compound interest?
Simple interest is based on the original principal. Compound interest can also earn interest on previously accumulated interest.
Can simple interest be used for every loan?
No. Loan calculation methods vary. Some loans use amortization, reducing balances, fees or other methods. Use the calculation method specified by the lender or agreement.
Does this calculator include fees or taxes?
No. The calculation uses only the principal, interest rate and time period entered.
Is this financial advice?
No. This calculator is intended for general educational and planning purposes.