Excel Extensions

What Are Extensions In Excel?

Excel Extensions in files are the secondary filenames added at the end of any filename to identify the application type such as .doc, .docx, .xls, .xlsx, .ppt, .pptx, .html, .gif, etc. These are three to four letters long, and attached to the primary filename. Extensions indicate the Excel file type and the format of the data it contains. They help users choose which application to open and run the specific file correctly.

For example, the below image shows an Excel worksheet containing employee appraisal and promotion eligibility details.

Excel Extension - Sample

We can save the above file using Extensions that best support the file and data type.

Excel Extension - Sample-format

Here we save the file in the name Excel Extension_Sample with the default Excel file extension .xlsx.

Key Takeaways
  • Excel Extensions are suffixes added to the file names after the dot sign. They define the specific file format and its data type.
  • We can use Extensions in Excel as follows: XLS and XLSX is the default Excel extension, XLSM is for the macro-enabled files, XLSB to reduce the file size, and XLAM if the Excel file contains add-ins.
  • To change the file format, go to FileSave As, the Save As window opens. Choose the required extension in the Save as type: field and click Save in the Save As window.

Where To Find File Extensions In Excel?

We will find the Extensions in the Save As window as the Save as type: options.

Excel Extension - Save as

If we are looking for the default Excel Extensions, we can save our file with the extension (*.xlsx). It is the default file format the OS recognizes, and users can use this first Save as type: option for saving their Excel workbooks to keep their file formats undistorted.

Likewise, we can also see the other available Extensions below the Workbook (*.xlsx) option, which are compatible with specific applications. We can choose the one that supports our Excel file type and data format.

Note: Go to the “Search” option next to the windows “Start” button – type “File Explorer Options” – in the “File Explorer Options” window, click on the “View” tab.

The Hide extensions for known file types option is selected, as shown below,

Excel Extension - Hide

Now, right-click on the Excel file and choose Properties to determine the file format type.

Excel Extension - Properties

The “Excel Extension_Sample Properties” window opens. In the “General” tab, we can see the file extension in the “Type of file:” field, as highlighted in the below image.

Excel Extension - Type

Top 5 Excel File Formats

The top five Excel Extensions or file formats we would typically require in our daily tasks are,

  1. XLSX
  2. XLSM
  3. XLSB
  4. XLS
  5. XLAM

#1 – XLSX

If we have not used any macros in our workbook, we can choose default Extensions, the commonly used one being the XLSX.

While the XLSX reduces the file size, it allows us to store and use all Excel functions, making file downloading and sharing straightforward and compatible with other software applications.

However, it is one of those Extensions which does not support VBA macros.

The steps to save with the XLSX extension are:

Step 1: In our workbook, go to FileSave As.

Excel Extension - Step 1
Excel Extension - Save as

Step 2: In the Save As window, choose the location where we want to save our file, enter the file name in the File name box, and select the Save as type: field as Excel Workbook (*.xlsx).

Excel Extension - Step 2

The XLSX extension is the first format on the Extensions list, in the Save as type: options.

Click the down arrow to choose it from the Save as type: field, as explained in the previous sections. And once we click Save, we will see the saved file in the selected location, as shown below.

Excel Extension - Step 2-saved

#2 – XLSM

When our workbook contains VBA macros, we cannot use Extensions, such as XLSX, to save the file, as they do not support VBA macros.

To ensure the macros run correctly, we can use other types of Extensions in Excel. In this scenario, we can use the XLSM extension i.e., the default file format for macro-enabled workbooks. Extensions like these make the files highly secure and protect from viruses.

The process to save with the XLSM extension is the same as the XLSX, except the Save as type: will be Excel Macro-Enabled Workbook (*.xlsm), as shown below.

Excel Extension - type 2 - Step 1

The XLSM Excel file format supports all Excel functions and formulas like the other Excel Extensions. However, it needs more disk space. Therefore, after we save the Excel file, it appears as shown below:

Excel Extension - type 2 - Step 2

[Note: The XLSX and XLSM use an XML format to store information].


Our Excel file will be slow if it is over 10 MB. When we save the Extensions XLSX and XLSM, it will slow down the file further.

We must use the XLSB file format while saving our Excel, in such scenarios. As the extension uses the binary format to store information, it takes less disc space, supports all Excel functions, and enables users to save macro-enabled files.

The process of saving a file with the XLSM extension is the same as that explained for the XLSX extension. But choose Excel Binary Workbook (*.xlsb) from the list as the Save as type: field options.

Type 3 - step 1

After we save the Excel file, it will appear as shown below.

Type 3 - step 2

#4 – XLS

The file format used to save Excel with a version before 2007 was XLS. After Excel 2007, it was replaced by the XLSX extension.

Though XLS files are no longer in use, many applications still support the file format. The reason is that users might need to open Excel files with a version older than 2007.

The process of saving a file with the XLSM extension is the same as explained for the XLSX extension. But we will see such files saved using the Excel 97-2003 Workbook (*.xls) file format available in the list of Extensions in Excel as Save as type: field options.

Type 4 - Step 1

[Note: If we try saving files with new Extensions using the XLS file format, we will get the below warning message.

Excel extension - Warning

To save the Excel file without the unsupported features, click Continue to complete the action.

Type 4 - Step 2

#5 – XLAM

To save our workbook containing Add-ins data, we can use the XLAM extension. It will ensure that the file works well, even if it includes VBA macros and forms.

Typically, we would either use Excel’s inbuilt add-ins or write macros and create user-defined functions to use as add-ins. We will then have to go to FilesOptionsAdd-ins or DeveloperExcel Add-ins to open the Add-ins window and enable the required add-ins.

And then, when we use the XLAM file format to save the file, we can use the additional functionalities efficiently every time we open an Excel workbook.

The process to save a file with the XLSM extension is the same as explained for the XLSX, except the Save as type: field will be Excel Add-in (*.xlam).

Type 5 - step 1

The XLAM Extension is not that common, still, we can launch it like a typical Excel file.

Type 5 - step 2

How To Change The Excel File Format Or Extension?

Consider the below Excel workbook with macros saved as an XLSM file.

Excel Extension - Change File format

To delete the macros and use the Extension, such as XLSX, to save the file with no macros, the steps are:

Step 1: Choose FileSave As.

Change File format - Step 1
Excel Extension - Save as

Step 2: In the Save As window, choose the location or folder where we want to save the Excel file.

Excel Extension - Change File format - Step 2

Step 3: Update the file name in the File name box.

Excel Extension - Change File format - Step 3

[Note: We do not need to enter the file extension while filling the File name field. Once we select the required file format from the Excel Extensions available as the Save as type: field options, the specific extension automatically gets added to the file name].

4: Choose the required file format in the Save as type: field. We will select the XLSX extension (Excel Workbook (*.xlsx)) in this case.

Change File format - Step 4
Change File format - Step 4 - type

Once we click Save in the Save As window, we will have the file saved with the updated extension in the required location.

Change File format - Step 4 - saved

Things To Remember

  • Excel Extensions ensure the specific features work efficiently without any errors. Hence, we must choose the right extension or file format for our Excel data and functionalities.
  • We must uncheck the Hide extensions for the known file types option in the View tab of the File Explorer Options window. It will make the file extensions visible in the Save As window.
  • The default file format for Excel without macros is XLSX.
  • When we get an error or warning message when saving files with Extensions in Excel that do not support specific features, if not required, we can proceed without the unsupported functions.

Frequently Asked Questions

1. Which Excel extension should I use?

We should use the Excel extension in the Save as type: field of the Save As window that best suits our file format and data type. The below image highlights the Extensions we can typically use to save our Excel files.

• If our Excel file does not contain macros, use the XLSX extension.
• If our Excel file contains macros, use the XLSM extension.
• If we want to reduce our Excel file size, use the XLSB extension.
• If our Excel version is older than 2007, use the XLS extension.
• If our Excel file contains Excel add-ins, use the XLAM extension.

Excel Extension - FAQ

2. What is difference between XLS and XLSX Excel Extensions?

The difference between XLS and XLSX are:

• The XLS file format arranges data as binary streams, while the XLSX extension uses the XML file format to store the data in a compressed XML file in ZIP format.
• The number of rows and columns in an XLS file is fewer than that in an XLSX file, but the XLS file size is comparatively larger than an XLSX file size.

3. What is the smallest Excel extension file type?

The smallest Excel extension file type we can use if our file is over 10 MB is XLSB. Otherwise, it is best to stick to XLSX or XLSM file formats.

Download Template

This article must help understand the Excel Extensions, with its formula and examples. We can download the template here to use it instantly.

Recommended Articles

This has been a guide to Excel Extensions. Here we use the steps to save the files in the top five excel file formats or extensions & a downloadable template. You can learn more from the following articles –

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