what file extension is excel

The file extension for Excel is .xlsx. This extension is used for Microsoft Excel 2007 (and later) workbooks. Excel files were previously saved with the .xls extension, but this was changed in 2007 to accommodate the new features of the software.

Here is a table that summarizes the file extensions for different versions of Microsoft Excel:

Version File Extension
Excel 97-2003 .xls
Excel 2007-present .xlsx
Excel 2008 for Mac .xlsb

.xls: The .xls extension was used for Excel workbooks from Excel 97 to Excel 2003. These files are based on the Binary File Format (BIFF), which is a proprietary format that is not as widely supported as the Open XML Format (OOXML) used by .xlsx files. As a result, .xls files may not be compatible with all applications, and they may not be able to take advantage of the latest Excel features.

.xlsx: The .xlsx extension is used for Excel workbooks from Excel 2007 and later. These files are based on the OOXML format, which is an open standard that is supported by a wide range of applications. OOXML files are also more efficient than BIFF files, which means that they are smaller and load faster.

.xlsb: The .xlsb extension is used for Excel workbooks that are saved in XML Binary Workbook (XLS) format. XLSX files are compressed, which can make them difficult to open or edit in some applications. XLS files are uncompressed, which makes them easier to open and edit, but they are also larger than XLSX files. XLS files are primarily used for sharing workbooks with users who may not have Excel installed.


In addition to the file extensions listed above, Excel also supports a number of other file extensions, including:

  • .xltm: Template file for Excel 2007 and later
  • .xltx: Template file for Excel 97-2003
  • .xla: Add-in file for Excel
  • .xlam: Add-in file for Excel 2007 and later
  • .xlw: Workspace file for Excel
  • .xlm: Macro file for Excel
  • .xml: XML file for Excel