Math Is Fun
Math Is Fun: Compound Interest Calculator
A calculator based on the compound interest formula that can be used to determine the Present Value, the Future Value, the Interest Rate, or the Number of Periods. You can select the type of compounding, the effective annual rate, and...
Thinkport Education
Maryland Public Television: Sense and Dollars
Engaging, fun tutorials and interactive games related to earning, spending, saving, and budgeting money.
Calculator Soup
Calculator Soup: Rule of 72 Calculator
Use the Rule of 72 to estimate how long it will take to double an investment at a given interest rate. Divide 72 by the interest rate to see how long it will take to double your money on an investment.