Enter principal, annual rate and time to get the interest earned and total amount.
Interest details
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Interest earned
$0.00
Enter principal, rate and time.
Principal
$0.00
Interest
$0.00
Total amount
$0.00
Formula: interest = principal x rate x time. Total = principal + interest. Simple interest does not compound: you earn the same amount every year.
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How simple interest works
Simple interest is charged only on the original principal, never on accumulated interest. That means you earn (or owe) the exact same dollar amount every year, which makes the math a single multiplication.
Simple vs compound
Compound interest earns interest on interest, so it grows faster every year. Simple interest is common for short-term loans, auto loans and some bonds; savings accounts and mortgages almost always compound. For compounding, use the compound interest calculator.
Interest = principal x rate x time. $10,000 at 5% for 3 years earns $10,000 x 0.05 x 3 = $1,500, for a $11,500 total.
What is the difference between simple and compound interest?
Simple interest applies only to the original principal, so earnings are flat each year. Compound interest applies to principal plus past interest, so it accelerates.
When is simple interest used?
Short-term personal loans, some auto loans, and certain bonds use simple interest. Most savings accounts, credit cards and mortgages compound instead.
Does the time have to be in years?
The rate and time must use the same period. With an annual rate, express time in years (6 months = 0.5).
Is my data uploaded anywhere?
No. Every calculation happens in your browser with JavaScript. Nothing you enter leaves your device.