By default Excel 2022 files are saved with this extension

Starting with Excel 2007 Microsoft introduced a series of new file formats to replace the .xls. Each of these new formats has different functionality and uses. It is important to be familiar with the different formats, particularly if you regularly work with large documents. This technical update details the file extensions available in Excel and when AMT recommends that these should be used. You can see the difference between two of the most commonly used file formats by downloading the files below and observing how long they take to open.

Inhaltsverzeichnis Show

What is an Excel file extension?
Why Excel File Extensions Matter
Excel File Extensions By Version
Other Excel File Extensions

These files do not contain real data. Please feel free to duplicate the data to increase the file size and see how it affects the file type’s load time.

Mock data XLSX
Mock data XLSB

What is an Excel file extension?


.xlsx	Excel workbook	This is the main replacement for the former binary .xls format. For enhanced security, this format does not support Excel macros. Underlying this format is a ZIP archive of XML documents.	The default Excel format if macros are not used in your model.
.xlsm	Excel macro-enabled workbook	Exactly the same as .xlsx, but with the ability to support Excel macros.	The default Excel format if macros are used in your model.
.xlsb	Excel binary workbook	An Excel macro-enabled workbook. The file information is stored in binary format rather than as XML documents.	This file format is approximately twice as fast as .xlsx at opening and saving Excel workbooks. This is particularly useful for very large files (greater than 10MB). This file extension cannot be used by non-Excel applications such as Bloomberg and Capital IQ, so if these systems access your Excel file, then this file format should not be used.
.xltx	Excel template	A template Excel workbook.	This format should be used if a standard Excel file is to be used as a starting point for other Excel workbooks.
.xltm	Excel macro-enabled template	A template Excel workbook with macro support.	This format should be used if a standard Excel file is to be used as a starting point for other Excel workbooks and contains macros.

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A file extension is the group of letters that appear after the last period in a file name. File extensions are usually 2 to 4 characters long, although they can be of any length. Excel uses a handful of standard extensions to disambiguate certain kinds of spreadsheet files.

The information in this article applies to Excel 2019, Excel 2016, Excel 2013, Excel 2010, Excel 2007, Excel Online, and Excel for Mac.

The current default file extension for an Excel file is XLSX. Prior to Excel 2007, the default file extension was XLS. The main difference between the two is that XLSX is an XML-based open file format and XLS is a proprietary Microsoft format. But, the newer versions of Excel save and open XLS files for the sake of compatibility with earlier versions of the program.

Determine if a file contains macros before you open it. Macros contain code that could damage files and compromise computer security if they come from untrusted sources. Excel files containing VBA and XLM macros use the XLSM extension.

XML stands for extensible markup language. XML is related to HTML, the extension used for web pages. Advantages of this file format include:

Smaller file sizes for storage and transfer.
Better recovery of information from damaged files.
Easier detection of files containing macros.

If an Excel file has either an XLTX or an XLTM extension, it is saved as a template file. Template files are used as starter files for new workbooks. Templates contain saved settings such as the default number of sheets per workbook, formatting, formulas, graphics, and custom toolbars. The difference between the two extensions is that the XLTM format can store VBA and XML macro code.

Macintosh computers do not rely on file extensions to determine which program to use when opening a file. However, for the sake of compatibility with the Windows version of the program, Excel for Mac uses the XLSX file extension.

Excel files created in one operating system can be opened the other. One exception to this is Excel 2008 for the Mac, which does not support VBA macros. As a result, it cannot open XLMX or XMLT files created by Windows or later Mac versions that support VBA macros.

To change an Excel format (and its extension), follow these steps:

Open the workbook and select File > Save As. In Excel 2019, select Save a Copy instead.
In the dialog box, accept the suggested file name or type a new name for the workbook.
In the Save as type or File Format list, choose the format for the resulting file.
Select Save to save the file in the new format and return to the current worksheet.

If a file is saved in a format that does not support all the features of the current format, such as formatting or formulas, an alert message box appears prompting you to continue or to cancel.

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Excel, as well as all of the core Microsoft Office applications, have gone through decades of version upgrades. Along with those upgrades came small tweaks to Excel file extensions to account for the differences between those Excel files.

It isn’t just version differences that spawn new file extensions. Some file extensions refer specifically to the type of file, such as whether it’s an Excel template or an Excel file that contains a macro.

If you understand all of the Excel file extensions, you’ll have a better handle on how to save your file in the file save dialogue box.

Why Excel File Extensions Matter

The extension of an Excel file provides you with important information about that file before you open it. It also lets you organize the files you save into your directories as template files, macro-enabled files, and more. With just a glance at the Excel file extension, you know more about the Excel file and what it’s used for.

Excel file extensions tell you:

Whether macros or VBA is included
If the file was saved with an older version of Excel
Whether the file format is based on XML documents or binary
The general legacy version the file was saved with
Whether the file is a template

You can see all of the file extensions in Excel by selecting File from the menu, select Save As, and then select the file type dropdown under the file name field.

As you can see, each of the file types have a descriptive name that helps with understanding what the file extension is for.

Excel File Extensions By Version

The first group of file extensions are related primarily to which version of Excel the worksheet was saved with. The following extension types are connected to the Excel versions shown here:

Excel 97-2003: *.xls
Excel 97-2003 template: *.xlt
XML Spreadsheet 2003: *.xml
Microsoft Excel 5.0/95 Workbook: *.xls
Excel 97-2003 Add-in: *.xlam
Excel 4.0: *.xlw
Microsoft Works: *.xlr

As you can see, the *.xls file extension is the default legacy Excel format for all versions of excel prior to Excel 2007.

From Excel 2007 onwards, the default file extension for any Excel file was (and remains) *.xlsx.

While Microsoft switching to the XLSX extension after Excel 2007 seems like a superficial naming convention change, the truth is that there was more change than just the file extension.

XLS stores Excel spreadsheets in a file format known as Binary Interchange File Format. This was a proprietary file format created by Microsoft.

With the release of Excel 2007, Microsoft changed the default to XLSX, which is based on the Office Open XML format. This is a method of saving spreadsheet information in an XML file.

What were the advantages of switching to this new method of saving Excel spreadsheet information? There are many.

Interoperable: Office Open XML formatted files can more easily be pulled into other applications that can read Office XML formats.
Extensible: External applications or programs can manipulate the contents of the underlying XML format — this means programmers can create software to edit Excel spreadsheets without ever opening the Excel application itself.
Safer from corruption: XML formatted files are less susceptible to corruption or damage than binary files like XLS files are.
Smaller: You can store more data in a smaller file when you use the XLSX format. Microsoft claims XLSX files are 75 percent smaller than XLS files.

If none of those advantages matter much to you, then you might be better off staying with the older default XLS Excel format. You do get two advantages when you do this.

The first is that XLS files tend to save and open faster. Secondly, Excel files with the XLS extension can be opened on every version of Excel, no matter how old.

Other Excel File Extensions

Now that you understand the difference between XLS and XLSX, it’s a little bit easier to decipher what all of the other Excel file extensions mean.

.xlsm: XML format Excel files that also support Excel macros
.xlsb: Binary format Excel files (older version) that also support Excel macros
.xltx: An Excel file saved as a template to be used as a starting point for future Excel workbooks
.xltm: A macro-enabled Excel file that’s saved as a template

Excel Template Files

If you’re unfamiliar with Excel templates, it may be a good time to learn about and start using them. If you find yourself creating a lot of spreadsheets that share the same formatting, formulas, or layout, a template can save you a great deal of time.

All you have to do to create a template is set up your formatting, layouts, and other aspects of your worksheet that you don’t want to recreate every time. Then save the file with one of the Excel file extensions listed above for template format.

In fact, when you open a new file in Excel, you can search through thousands of premade templates across many categories.

Excel isn’t limited to opening only files with Excel file extensions. When you open a file in Excel and select from the file type drop box, you’ll see a long list beyond what’s listed in this article.

This is because there are non-Microsoft file formats that are also supported in Excel.

*.xml: Any spreadsheets from applications that stored the sheets in XML Spreadsheet 2003 format, or straight XML formatted data files.
*.prn: Lotus spreadsheets
.txt: Tab-delimited or Unicode text files
.csv: Comma-delimited text files
.dif: Data Interchange Format text files
.slk: Symbolic Link Format text files
.dbf: dBase data files
.ods: Opendocument spreadsheets (Google Docs or OpenOffice)
.pdf: Retains the formatting of data when you open PDF data files
.xps: XML Paper Specification data files

Keep in mind that depending on the Excel version you’re using, not all of these file types will display as options when you’re saving or opening files.