The difference between .xls vs .xlsx – Microsoft Excel

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Microsoft Excel utilizes the XLS vs XLSX formats to store either financial or mathematical data. Most businesses and other professional establishments use its spreadsheet when presenting a report to visualize data through the use of charts and tables.

However, for casual users, the one-letter difference between XLS and XLSX may be confusing at first. Thus, this article discusses a more in-depth discussion about XLS vs. XLSX and their other functions.

What Is XLS?

XLS files are commonly used to organize, analyze, manipulate, or visualize data, especially in establishments such as schools, businesses, or even for personal use at home. Upon opening the Excel spreadsheet, a blank worksheet is shown and a spreadsheet that consists of a table with numerous columns and expansive rows and cells that contain data that may be entered manually.

XLS files may also be referred to as an Excel spreadsheet. This is because XLS is known to be an old version of Excel’s file extension that has a format that utilizes proprietary binary. This kind of formatting is used to store documents in Microsoft Excel, which is more formally known as BIFF or Binary Interchange FileFormat.

The XLS formatting was first introduced in the year 1987, the same time Microsoft Excel was released. With this, using XLS files to save spreadsheets became one of the popular methods when using Microsoft Excel, not until the updated version of Excel was released in 2007. XLS files were replaced by the XLSX format, which is more formally known as the Microsoft Excel Open XML Spreadsheet, and became the current standard of saving Excel spreadsheets.

What Is XLSX?

With its update, Microsoft Office 2007 added the letter “x” to many of its file extensions. These include “docx” for Word files, and “pptx” for PowerPoint files. Its Excel files also upgraded and became “xlsx” from “xls”. This update includes a folder hierarchy, in which small files are included in a very detailed manner. This type of formatting can also be compressed into a .zip folder.

Also known as open XML, XLSX is the updated version of Microsoft Excel’s file extension for their spreadsheets. XLSX is known to be more diverse since it is also compatible for software outside Windows such as MacOS, Android devices, and iOS devices. XLSX files also include visual basic for applications such as tables for pivots and tools for graphing.

XLSX also contains Excel operations that are beyond the plain data provided by XLS only. These include more advanced formulas, charts, and formats. Although it is not created for more advanced manipulation outside of Microsoft Excel, it can still retrieve plain data from other applications and read from it.

Similarities between the two

● Functionality

In terms of functionality, XLS and XLSX in Microsoft Excel can both be used for financial applications such as saving data for financial reports and utilizing models for mathematics. This characteristic makes both files ideal for mathematical calculations. They also both contain linking features, which make it easier to hyperlink a file on an Excel cell.

● Graphics

XLS and XLSX files both contain multiple worksheets upon opening the Excel application. With this, both files also include graphical and visual representations such as tables and graphics to present data. A filter data was also used to display data in a convenient and organized manner. Though presenting directly from Microsoft Excel may be inconvenient, presenting charts through this application, and then putting it on a PowerPoint presentation is a great way of running and presenting reports.

● Versatility

Although they cannot be used for storing and modifying big chunks of data, since both programs are easy to use, these two types of Excel files can be mostly found in business establishments and professional contexts such as in universities, corporations, small enterprises, or even for personal home use.

XLS vs XLSX – what makes one better than the other

Due to its numerous updates and improvements with technology, XLSX is considered to be the standard when it comes to saving Excel files.

The significant thing about the XLSX file format is that it saves time from recovering or retrieving data lost since its updated Office application can easily detect defects that may happen while working on the file or document. Other factors include:


The main comparison between these two files is that XLS uses the standard binary format, while XLSX applies the updated version that is based on the format of XML. In addition, the size of XLSX files can be compressed and reduced when they are changed to XLS files.


With regards to speed, regardless of its updated version, XLSX is known to be slower than XLS files, especially those that need a formula that is complex for bigger sets of numbers or data.

● Storage

In terms of storage, XML files utilize .zip compression techniques to improve the data storage of the device. Hence, with its newer updates, XLSX is designed to have a file size that is smaller than XLS files.

● Compatibility

Although XLSX is compatible with more devices than XLS files, the latter is considered to be more readable across all versions of Microsoft Excel. XLSX can only be read in 2007 and higher versions. Moreover, more spreadsheets are available in XLS files regardless if they include or support Macros. On the other hand, XLSX files are not.

● Design

Due to its design of preventing data loss from damaged files, an XLSX file is more robust than an XLS file and its binary format.

● Security

Due to its versatility, the XLSX format provides more security and transparency in its files. This means that it is easier to remove sensitive information such as personal data and other business-related information. This is to allow IT specialists to identify files with embedded codes through the use of their unique format.

XLSX files can also update to improve its security from documents that have a code embedded in it or even in macros files. This is because newer versions of Microsoft Office (starting from 2007) do not include embedded codes in their file formats.


In conclusion, both XLS vs XLSX can systematically store mathematical and financial data. They also both contain visual characteristics such as spreadsheets with columns and rows that make up a grid.

The main difference is that XLSX, and its Open XML, format is the newer version of XLS, since the latter still uses the old format of proprietary binary. In addition, since XLSX is newer, its format cannot be read by old versions of Microsoft such as Excel 2003 and other earlier versions. However, because of its security and technological upgrade, XLSX is known to be better than XLS since it is easier to detect malfunctions when working on a document.


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V. (2022b, February 16). 7 Difference Between XLS And XLSX. Viva Differences.