Conditional formatting applies rules to cell appearances for easier viewing and analysis of large numbers. For example, cells with a value of less than 50 percent can be automatically colored red, and cells with a value greater than 50 percent can be automatically colored green. This way, if you're looking for larger numbers, you can start by looking for the green cells.
In Microsoft Office Excel 2003, applying conditional formatting means going to the Format menu and then manually entering the values and type of format to be applied. In Microsoft Office Excel 2007, you can click Conditional Formatting in the Styles section of the Home tab, and then select the preconfigured rule that you want to apply. You can also choose from predefined formatting options like Data Bars, Color Scales, and Icon Sets. For more advanced scenarios, select Manage Rules from the Conditional Formatting options.
Published on Microsoft.com: February 15, 2008