Difference Between XLS and XLSX

Difference Between XLS and XLSX


XLS and XLSX are two file extensions that are used by the Microsoft spreadsheet application named Microsoft Excel. The difference between XLS and XLSX is obvious. XLS is an Excel spreadsheet and this file extension is created by Microsoft for use with Microsoft Excel. This file format is known as the Binary Interchange File Format (BIFF).

What is XLS?

XLS is very common and everyone knows this spreadsheet as it is the default format of Microsoft Excel since it was first made up till 2003. In the Microsoft Office 2007 release, Microsoft made a decision to modify the default file format to a diverse format. He then added an extra x for all document extensions for Excel. As a result, this ended up as XLSX.

What is XLSX?

XLSX is a Microsoft Excel spreadsheet which is developed by Microsoft for Windows, MacOS, Android and iOS. XLSX is a totally different from the older file format that is used in older Excel applications. It is not readable Excel versions earlier to 2007.

Difference Between XLS and XLSX

As always, back to front compatibility is always a right of way for Office applications. Regardless of adopting and promoting the new format of XLSX, newer Excel versions can be open and save documents to the older XLS format. Though it is worth noting that Microsoft Excel 2007 has thrown down support for older file formats that were usually found in MS-DOS.

If we take a deep look into the differences between XLS and XLSX, we’ll find that the way the information put in storage is very different for both XLS and XLSX formats.

As we mentioned above that XLS is based on Binary Interchange File Format (BIFF) and the information is directly stored to a binary format. Whereas the XLSX is based on the Office Open XML format, a file format that was derived from XML.

The information in the XLSX file is stored in a text file that uses XML to describe all its parameters. As XLSX is stored in a text file format, Microsoft decided to eliminate macro support for this file format. In its place, they assigned an entirely different file extension to allows the use of macros and it is named XLSM.

The older XLS file extension does not have this problem and able to hold spreadsheets that contain macros or not.


XLS is readable by all Microsoft Excel versions whereas XLSX is only readable by versions 2007.

XLSX is not able to support macros despite the fact XLS does.

XLS is the default file format for the 2003 Excel version and older while XLSX for versions since 2007. XLS is a proprietary binary format while XLSX is based on Office Open XML format.

for more posts, keep visiting diffbt.com