➗ Simple Interest Calculator
Simple interest is charged only on the original amount, not on interest already added. It is used for many short-term loans, car loans in some states, and some bonds and CDs.
How the Simple Interest Calculator works
Multiply the principal by the yearly rate and by the number of years. Because interest never earns more interest, the balance grows in a straight line.
Step-by-step calculation
- 1Enter the principal.
- 2Enter the yearly rate and time.
- 3Multiply P × r × t.
Worked example
$10,000 at 5% for 3 years: interest = 10,000 × 0.05 × 3 = $1,500, so the total is $11,500.
Simple Interest Calculator examples
| Principal ($) | Interest |
|---|---|
| 5,000 | $750.00 |
| 7,500 | $1,125.00 |
| 10,000 | $1,500.00 |
| 12,500 | $1,875.00 |
| 15,000 | $2,250.00 |
Other inputs kept at the calculator's default values. Results calculated by this calculator.
Why use a Simple Interest Calculator?
Calculate interest on short loans, notes and simple deposits.
Important factors that can affect your results
- Time in years (months ÷ 12).
- Simple vs compound interest.
- Fees.
Frequently asked questions
How is this different from compound interest?
Compound interest adds interest to the balance so it earns more interest. Over long periods compound interest grows much faster.
Can I use months?
Yes. Enter time as a fraction of a year, for example 18 months = 1.5 years.
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Last reviewed November 2026 · How we build and check our tools · Report a problem