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Financial

Simple Interest Calculator

Variable Legend

I= interest earnedP= principalr= annual rate (decimal)t= time in years

Simple interest formula

Interest grows linearly with time.

Interest
Total amount

Find principal

How much was originally invested.

Find rate

Solve for the annual interest rate.

For informational purposes only. This tool does not constitute financial advice. Consult a qualified financial adviser before making investment or financial decisions.
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Pro Tip

Always verify your input values before calculating. For simple interest, small input errors can compound and significantly affect the final result.

Difficulty:Beginner

Did you know?

Simple interest is used for short-term loans, car loans, and some savings accounts. For long-term investments, compound interest grows significantly faster.

Mathematically verified
Reviewed May 2026
Used 44K+ times
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