XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.

If you're still saving Excel spreadsheets with a three-letter .xls extension, you're lugging around a digital anchor from the era of dial-up. Beyond being a 1990s relic, these legacy files are slow, ...

The cells in a Microsoft Excel spreadsheet can hold various types of numerical data, including fractions and percentages. If some or all of your cells contain fractions, Excel enables you to convert ...

How to force a consistent phone number format in Microsoft Excel Your email has been sent Combine an Excel custom format with data validation and remove the pressure ...

An icon in the shape of a lightning bolt. Impact Link When you enter a date that's formatted with slashes, Excel will recognize it as a date. For example, Excel will automatically choose the date ...

How to add a conditional format that highlights groups in Excel Your email has been sent The article, How to use a border to discern groups more easily in Microsoft Excel, shows you how to use a ...