Let’s break the file extension in three parts:
- The first and second letters of the file extension refer to the application:
xl
= Excel
- The third letter refer to the specific file type:
s
= Spreadsheett
= Templatea
= Add-in
- The last letter specifies whether the file format is XML based or it supports macros:
x
= XML based file format, can’t store VBA macro codem
= Macro-enabled and XML based file formatb
= Binary file format (support faster loading and saving). This non-XML based file format can store VBA macro code.
Excel 2007-2019 file extensions
.xlsx
= Excel Workbook
It is the default Excel file format.
.xlsm
= Excel Macro-Enabled Workbook
The file format with all macros it contains enabled.
.xlsb
= Excel Binary Workbook
The binary file format, optimized for the faster loading of really large workbooks with tons of data.
.xltx
= Excel Template
An Excel template file can use to generate new workbooks containing the same layout and content as the template.
.xltm
= Excel Macro-Enabled Template
An Excel template file format with all the macros it contains enabled.
.xlam
= Excel Add-in
An Excel add-in is a workbook that gives additional functionality to any workbook. Its open automatically when it starts-up.
Excel 97-2003 file extensions
.xls
= Excel Workbook
This binary file format is used by earlier versions of Excel 97 through Excel 2003.
.xlt
= Excel Template
Binary files for an Excel template.
.xla
= Excel Add-in
Binary files for an Excel add-in.
Open source spreadsheet programs file extension
.ods
= OpenDocument Spreadsheet
You can save (or open) a workbook in ODF format with an .ods
filename extension that’s used by other Office suites of programs, such as StarOffice OpenOffice.
Other file formats supported in Excel
.csv
= Comma delimited text file.dbf
= dBase file format.dif
= Data Interchange Format.htm, .html
= Web-Page, saved in a folder, all supporting files saved in that folder..mht, .mhtml
= Single File Web Page, includes all supporting files, such as images.pdf
= Portable Document Format, this format preserves file formatting when sharing with others..prn
= Lotus space-delimited format..slk
= Symbolic Link Format.txt
= Plain text file.xml
= XML file format.xps
= XPS Document