Simple Interest
Simple interest is calculated only on the original principal, never on interest already earned or owed. $1,000 at 5% simple interest earns exactly $50 a year, every year. It's the opposite of compound interest, where earnings themselves start earning.
Most auto loans and some personal loans use simple interest, which works in your favor — paying early reduces the principal that interest is charged on. Savings and investments, by contrast, benefit from compounding, which is why the distinction matters.
Put it to work
Compound Interest Calculator
See how your savings grow with compound interest and monthly contributions — final balance, interest earned, and a year-by-year growth table.
Loan Calculator
Calculate the monthly payment, total interest, and payoff date for any personal, auto, or fixed-rate loan — and see how extra payments shorten it.
Auto Loan Calculator
Car payment with the real numbers: sales tax, fees, trade-in credit — even negative equity. See the monthly payment and the true total cost.