Doubling Your Money This calculator demonstrates the power of compound interest. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Share | Have A Question About This Topic? Address Thank you! Oops! Related Contents The Power of Compound Interest Learn how to harness the power of compound interest for your investments. A Penny Saved is Two Pennies Earned Here are some simple and inexpensive energy-saving tips that may help you save money. Paying Off a Credit Card Enter various payment options and determine how long it may take to pay off a credit card.