A large assortment of practical and easy to use financial calculators.
http://accountant.intuit.com/practice_resources/calculators/
Examples:
How long will it take to pay off my credit card?
How long will my retirement savings last?
Traditional IRA or a Roth IRA?
How much should I save each month?
This calculator is designed to show you ten different financial ratios. Financial ratios are used as indicators that allow you to zero in on areas of your business that may need attention. Areas such as solvency, liquidity, operational efficiency and profitability.
http://www.cpasitesolutions.com/content/calcs/Ratios.html