XLS vs. XLSX
The current default file extension for an Excel file is XLSX. Prior to Excel 2007, the default file extension was XLS. The main difference between the two is that XLSX is an XML-based open file format and XLS is a proprietary Microsoft format. But, the newer versions of Excel save and open XLS files for the sake of compatibility with earlier versions of the program.
XML and HTML
XML stands for extensible markup language. XML is related to HTML, the extension used for web pages. Advantages of this file format include:
Smaller file sizes for storage and transfer. Better recovery of information from damaged files. Easier detection of files containing macros.
XLTX and XLTM
If an Excel file has either an XLTX or an XLTM extension, it is saved as a template file. Template files are used as starter files for new workbooks. Templates contain saved settings such as the default number of sheets per workbook, formatting, formulas, graphics, and custom toolbars. The difference between the two extensions is that the XLTM format can store VBA and XML macro code.
Excel for Mac
Macintosh computers do not rely on file extensions to determine which program to use when opening a file. However, for the sake of compatibility with the Windows version of the program, Excel for Mac uses the XLSX file extension. Excel files created in one operating system can be opened the other. One exception to this is Excel 2008 for the Mac, which does not support VBA macros. As a result, it cannot open XLMX or XMLT files created by Windows or later Mac versions that support VBA macros.
Change File Formats With Save As
To change an Excel format (and its extension), follow these steps:
