Difference Between xls and xlsx in Microsoft Excel

xls vs xlsx in Microsoft Excel

If you have been managing your data in a spreadsheet called Excel, developed by Microsoft, you are probably aware of the file extensions xls and xlsx. Excel is one worksheet that allows one to arrange and organize huge amount of data systematically. Sorting, filtering, using formula, and making suitable changes in data is easy and simple in Excel. In fact, Excel helps you understand what your data can do for you. But many remain confused by differences between xls and xlsx file extensions. This article attempts to highlight these differences to enable users to save their data in a format that is more suitable for their requirements.


Files created in versions of Excel prior to 2007 are stored in this format. If you try to open such file extensions with Excel 2007, it opens them in compatibility mode and you get to make use of several new features.


This is the default format for all files created in Excel version of 2007. It is actually a special kind of file that is compressed and contains all the data and formulae’s in a zipped file. You can unzip the file using XP or Vista to see the internal structure.

The extra x in file extension stands for XML or Open XML format. All information in files saved in xlsx format is stored in a file that makes use of XML.

What is the difference between xls and xlsx?

• Excel worksheet by Microsoft is a wonderful tool to handle data of all kinds and the files saved were in the format xls prior to Office 2007. In versions since Office 2007, file extension type xlsx is being used.

• Xlsx is Open XML format, whereas xls was in a binary format.

• Xls files can be opened by all versions of Excel, but not xlsx files.