Simple Interest Calculator
Get a quick simple-interest estimate when interest is charged on the original principal only.
Calculator
Simple Interest Calculator
Enter the original amount borrowed or invested.
Use the annual rate stated in the agreement.
Enter the total time period in years.
Example values are loaded.
Result
Your result
At 5.5% simple interest for 3 years, $5,000.00 grows to $5,825.00.
Interest
$825.00
Total amount
$5,825.00
Interest per year
$275.00
Simple interest inputs
Next steps
Compare before you move on
Most people use one calculator to answer the first question and a related tool to pressure-test the decision.
Borrowing
Loan Calculator
Estimate monthly loan payments, total interest, and total repayment with a standard amortized loan formula.
Savings
Compound Interest Calculator
Project future savings growth with a starting balance, one or more monthly contributions, and an expected annual return.
Debt
Debt Payoff Calculator
Estimate how long it could take to eliminate a balance based on your interest rate and monthly payment.
What this calculator shows
Simple interest is a straight-line calculation that does not earn or charge interest on prior interest.
It is useful for quick planning and for products that explicitly use simple interest instead of compounding.
How to use it
- 1. Enter the principal amount.
- 2. Add the annual interest rate and total time in years.
- 3. Review the interest amount and the total after interest is applied.
Formula and assumptions
Simple interest = principal x rate x time.
Total amount = principal + simple interest.
Notes
For accounts or loans that compound, use the compound interest calculator instead.
Worked example
A $5,000 balance at 5.5% for three years is a useful side-by-side comparison with compound growth.
This example uses the default sample inputs loaded on reset. It does not update with the live calculator entries above.
Interest
$825.00
Total amount
$5,825.00
Interest per year
$275.00
Feedback
Found a problem on this page?
Report confusing fields, broken math, or missing assumptions with the exact inputs you used so the issue can be reproduced.
FAQ
FAQ
When should I use simple interest instead of compound interest?
Use simple interest only when the loan or investment terms actually use it, or when you need a quick straight-line estimate.
FAQ
Why is the result lower than compound growth?
Because the calculation does not add interest to the base each period. You only earn or pay interest on the original principal.