Difference Between XLS and XLSX

Among the Microsoft Excel spreadsheets, XLS and XLSX are two of them commonly used to create mathematical models and store financial data. In worksheets, these files store data that consists of cells arranged as a grid of columns and rows. Excel spreadsheets might also consist of mathematical functions, charts, and several types of cell formatting.  

When it comes to business, these spreadsheets are often used in them. The main focus is on mathematical computations performance and storing financial data. In this article, differences between XLS and XLSX are highlighted with their other details. 


The main difference between the XLS and the XLSX is that the default file format of XLS is the Excel version of 2003. On the flip side, for versions since 2007, XLSX is the file format. When it comes to Microsoft Excel, XLS is its older version, whereas XLSX is its latest version. 


For an excel spreadsheet, XLS is an abbreviation. It is known for a spreadsheet file format by Microsoft for use with Microsoft Excel. Since it is established upon BIFF or binary interchange file format, the storage of data is in the format of binary. 

XLSX is a spreadsheet of Microsoft Excel which is manufactured by Microsoft for iOS, Mac OS, Android, and windows. It features graphing tools, pivot tables, calculation, and a macro programming language called Visual Basic for Applications. It also consists of a folder structure, with files that are small covering every detail. 

Comparison Table Between XLS and XLSX 

Parameters of ComparisonXLSXLSX
VersionOld versionLatest version
Based uponBinary formatOffice Open XML format
Data holdLesser quantityLarger quantity
Columns and rows capacityLess More capacity than XLS
File sizesLargerLesser than XLS

What is XLS?  

XLS stands for the spreadsheet of Excel. In other words, an XLS file is simply a spreadsheet file that is created by Microsoft Excel or by another spreadsheet program it is exported, for instance, Apple Numbers or open office calc. This file might also store charts, formatting, mathematical functions, and styles.  

XLS consists of one or more worksheets and displays and stores data in the format of a table. A proprietary format is used by Microsoft Excel files to store Microsoft Excel documents. This type of file format is called the binary interchange file format or BIFF.  

With the release of Excel, the XLS binary format came into play in 1987. This file became one of the most popular file types to save spreadsheets until Excel 2007 was released. XLS files can also work in MS Excel 2007.  

XLS files might be encountered in business environments, schools, and homes while visualizing, manipulating, analyzing, and organizing data. Each worksheet consists of a spreadsheet that contains a table with columns and rows and in a table, the cells might contain data that is manually entered or the results computed from the other cells’ data. 

What is XLSX?  

XLSX is a well-known format for documents of Microsoft Excel that was introduced with the release of 2007 Microsoft Office by Microsoft. It is based upon structure organized according to the conventions of Open Packaging, which is outlined in Part 2 of the standard ECMP- 376 of OOXML.  

The new format is a package of zipping that consists of several XML files. The underlying files and structure can be examined by generally unzipping the .xlsx file. In 2007, this file format was introduced and uses the standard of open XML adapted back in 2000 by Microsoft.  

Previous to XLSX, the XLS common file format was used that was purely file format of binary. This new file kind has added advantages of well-formatted images representation, fewer changes of corruption, and small file sizes. In the early 2000s, Microsoft decided to accommodate the Office Open XML standard.  

The official file format is available from Microsoft online. The XLSX file renames it to the ZIP file just by changing its extension. Then extract to view the constitute files of this workbook by excel. There is only one XML file, for each worksheet of excel contained in a workbook. 

Main Differences Between XLS and XLSX 

  1. In terms of version, XLS is the default version of 2003’s Microsoft Excel. On the other hand, XLSX is the default version of 2007’s Microsoft Excel.
  2. The information of XLS is stored in the format of binary. It is based upon the format of BIFF or Binary Interchange File Format. Meanwhile, the information of XLSX is stored in the text file with XML. It is based upon the format of Office Open XML.
  3. Extension’s file of XLS is not zip compressed. On the flip side, extensions files of XLSX are zip-compressed.  
  4. On a large set of data, those files with the usage of complex formulas tend to be quite faster in XLS. Conversely, speed performance is tended to be quite slow on files with the requirement of a complex formula on data with a large set in XLSX.  
  5. The XLS file extension support macro and can hold spreadsheets that consist of macros or not. In contrast, XLSX fails to support macro because Microsoft decided to eliminate the support of macro in this file format and assigned XLSM for using macros.


It can be concluded that both XLS and XLSX are two of the Microsoft Excel spreadsheets which are commonly used to create mathematical models and store financial data. XLS is based upon binary format. In contrast, XLSX is based upon office open XML format. When it comes to Microsoft Excel, XLS is its older version, while XLSX is its latest version.  

The default file format of XLS is the Excel version of 2003. Meanwhile, for versions since 2007, XLSX is the file format. XLS holds data in lesser quantities, whereas XLSX holds data in larger quantities. When it comes to columns and rows, XLS has less capacity to support columns and rows. Conversely, XLSX has more capacity for columns and rows than XLS. 


  1. https://www.nature.com/articles/cdd201522
  2. ftp://ftp.nara.wide.ad.jp/pub/lang/R/CRAN/web/packages/xlsx/xlsx.pdf
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