All About Excel Files (Types, Extensions, Open, Merge, Etc. )

What Are the Available File Types That Are Supported in Excel?

Excel supports 3 file formats. Their names, extensions, and details are in separate lists below.

1.1 Excel Files Format

Name	Extension	Details
Excel Workbook	.xlsx	The Excel 2010 and Excel 2007 default XML-based file format.
Excel Macro-Enabled Workbook	.xlsm	Stores Excel 4.0 macro sheets or VBA macro code.
Excel Binary Workbook	.xlsb	Excel 2010 and Excel 2007’s binary file format (BIFF12).
Excel Template	.xltx	For both Excel 2010 and Excel 2007, the default file format for an Excel template.
Excel Macro-Enabled Template	.xltm	Stores Excel 4.0 macro sheets or VBA macro code for template.
Excel 97-2003 Workbook	.xls	Excel 1997 and Excel 2003’s binary file format (BIFF8).
Excel 97-2003 Template	.xlt	Excel 1997 and Excel 2003’s binary file format (BIFF8) for template.
Microsoft Excel 5.0/95 Workbook	.xls	Excel 5.0/95’s binary file format (BIFF5).
XML Spreadsheet 2003	.xml	File format for XML Spreadsheet 2003 (XMLSS).
XML Data	.xml	Data format in XML.
Excel Add-In	.xlam	The XML-based Add-In format for Excel 2010 and Excel 2007, which supports macros.
Excel 97-2003 Add-In	.xla	The XML-based Add-In format for Excel 1997 and Excel 2003, which supports macros.

1.2 Text Format

Name	Extension	Details
Formatted Text (Space delimited)	.prn	Lotus space-delimited format.
Text (Tab delimited)	.txt	Ensures that tab characters, line breaks, and other characters are properly understood when saving a workbook as a tab-delimited text file for usage on a different Microsoft Windows operating system.
Text (Macintosh)	.txt	Same as Text (Tab delimited) but works in the Macintosh operating system.
Text (MS-DOS)	.txt	Same as Text (Tab delimited) but works in the MS-DOS operating system.
Unicode Text	.txt	Worksheet is saved as Unicode text.
CSV (Comma delimited)	.csv	Enables the usage of a workbook on another Windows operating system by saving it as a comma-delimited text file.
CSV UTF-8 (Comma delimited)	.csv	Same as CSV (Comma delimited) but allows special characters.
CSV (Macintosh)	.csv	Same as CSV (Comma delimited) but works on the Macintosh operating system.
CSV (MS-DOS)	.csv	Same as CSV (Comma delimited) but works on the MS-DOS operating system.
DIF (Data Interchnage Format)	.dif	Format for Data Interchange.
SYLK (Symbolic Link)	.slk	Format for Symbolic Link.

Note: All formatting is lost when you save a workbook in text format.

1.3 Other File Formats

Name	Extension	Details
OpenDocument Spreadsheet	.ods	You can save Excel 2010 files so they can be opened in spreadsheet software like Google Docs and OpenOffice.org Calc that supports the OpenDocument Spreadsheet format.
PDF	.pdf	Portable Document Format (PDF).
XPS Document	.xps	This file format allows file sharing and maintains document formatting.

1.4 File Formats That Use Clipboard

The Microsoft Office Clipboard supports the following listed file formats. You can paste data from this clipboard to Excel easily.

Name	Extension	Details
Picture	.wmf or .emf	Format for pictures in Windows Metafile (WMF) or Windows Enhanced Metafile (EMF).
Bitmap	.bmp	Format for pictures in Bitmap format (BMP).
Formatted text (Space-delimited)	.rtf	Format for Rich Text (RTF).
Embedded object	.gif, .jpg, .doc, .xls, or .bmp	Format for Microsoft Excel objects.
Linked object	.gif, .jpg, .doc, .xls, or .bmp	Format for OwnerLink, ObjectLink, Link, or Picture.
Office drawing object	.emf	Format for office drawing object or Picture.
Single File Web Page	.mht, .mhtml	Format for Single File Web Page (MHT or MHTML).
Web Page	.htm, .html	Hypertext Markup Language (HTML).

1.5 File Formats That Are Not Supported in Excel

The file formats that are not supported in Excel are listed below with extensions and details.

Name	Extension	Details
Excel Chart	.xlc	File types for Excel 2.0, 3.0, and 2.x
WK1, FMT, WK2, WK3, FM3, WK4	.wk1, .wk2, .wk3, .wk4, .wks	File formats for Lotus 1-2-3 (all versions)
Microsoft Works	.wks	File formats for Microsoft Works (all versions)
DBF 2	.dbf	File formats for DBASE II.
WQ1	.wq1	File formats for Quattro Pro for MS-DOS.
WB1, WB3	.wb1, .wb3	File formats for Quattro Pro 5.0 and 7.0 for Windows.

1.6 How to Open or View Unsupported File Formats in Excel?

To open or view unsupported file formats in Excel, search file format converters online for file types that Excel does not support.
Use the converter to export into a file format that Excel supports.

2. Overview of Excel File Extensions

Each format and extension differs from others in different criteria.

2.1 Differences Between xlsx vs. xls Format

The .xls file is larger than the .xlsx file.

The row and column numbers are also significantly different. The .xls file has a row limit of 65,536 (216) and 256 columns (IV).

The .xlsx file has a row limit of 1,048,576 rows (220) and 16,384 columns (214) or column XFD.

Feature	XLS (Excel 97-2003 Workbook)	XLSX (Excel Open XML Workbook)
File Format	Binary	Open XML
File Extension	.xls	.xlsx
File Size	Larger	Smaller
Compatibility	Older Excel versions may require a compatibility pack	Widely compatible with modern Excel versions
Features	May lack some advanced features available in newer Excel versions	Supports all features introduced in Excel 2007 and later
Security	Potentially higher security risks due to the binary format	Improved security features with XML-based structure
Data Recovery	More challenging	Easier due to the XML-based structure

2.2 Differences Between xlsx vs. xlsb Formats

Feature	XLSX (Excel Workbook)	XLSB (Excel Binary Workbook)
File Format	XML-based format	Binary format
Storage	Uses separate XML files within a compressed folder	Uses a binary format
Human-Readability	Human-readable, can be easily inspected	Not human-readable, as it is in binary format
Compatibility	Widely supported by various spreadsheet software and tools	Supported by Microsoft Excel; may have limited support in third-party applications
File Size	Tends to be larger due to XML-based structure	Tends to be smaller due to binary format, potentially more efficient with large datasets
Performance	Slower in some scenarios, especially with very large datasets	May offer faster calculations and smaller file sizes in some cases, especially with complex calculations and large datasets
Use Cases	Standard choice for general-purpose spreadsheet work	Considered when dealing with very large datasets or when optimizing for performance within the Microsoft Excel ecosystem
Versatility	Versatile for sharing data across different platforms	May have limited compatibility outside of Microsoft Excel

2.3 How to Check the Excel File Extension

Click on the File tab.
Click on the Save As pane to see the file extension in the marked box.
The file has a .xlsx extension.

2.4 How to Change the Excel File Extension

Follow the steps above and click on the arrow beside the file extension.
You can change the file type from the dropdown menu.
Choose your desired extension and click on Save.

2.5 How to Save Macro-Enabled Files in Excel

Choose Excel Macro-Enabled Workbook(.xlsm) from the dropdown.
Click the Save icon.

3. How to Open Excel Files

Select any Excel file on your PC.
Right-click on the file and select Open from the context menu.
Select Excel from the side menu.

3.1 How to Open Multiple Excel Files at Once in One Click

Put the files that you want to open with a click in a folder on your PC.

In Excel, click on the File tab from the Excel ribbon.

Select Options from the side menu bar.

Go back to the folder and copy the address.

Go to the Advanced >> General. Paste the address in the At startup, open all files input box.

If you open the Excel app, it will open the files in that folder automatically.

Opening multiple excel files at once in one click

Click on this image for a better view

3.2 How to Open Two Excel Files Side by Side

Open two Excel files.

Go to the View tab of any of the Excel files.
Click the View Side by Side option in the Window group.

You’ll see the files get positioned like the following image.

4. How to Combine/Merge Multiple Excel Files

The following image shows that we have two Excel files in a folder named 1. January_Data and 2. February_Data.

In 1. January_Data, we have Product ID, Product Name, Purchase Date, Price, and Payment Method of a few items for January.

You have another file named 2. February_Data contains similar data in the same format for February.

In the first January_Data file, change the dataset into a table using the Ctrl+T shortcut.

Select the table and rename it as Payment_Data.

Do the same for the file February_Data.

Open a blank Excel workbook and click on the Data
Go to Get Data >> From File >> From Folder.

Select the New Folder and click on Open.

Click Combine and select Combine & Load from the dropdown menu.

You’ll get your common table name.
Select that and click on OK.

The data in two Excel files will be combined into one Excel file.

5. How to Use Excel AutoSave

5.1 Turn On AutoSave in Excel

Go to File >> Options >> Save.
In the Save section, under Save Workbooks check the tick mark on the AutoSave files stories in the Cloud by default in Excel.
Click the OK button.

It will save the file automatically in the AutoRecover file location.

5.2 Change AutoSave Time in Excel

Check the tick mark on the Save AutoRecover information every and set the time of your preference.
In the following image, we set the time to every 10 minutes.

5.3 Turn Off AutoSave in Excel

Click on the circle beside AutoSave on the Quick Access Toolbar.

You’ll see color changing, which means it has been turned off.

5.4 Where Are Excel AutoSave Files Stored?

Go to the File tab and click on Open.
Double-click on the shared Onedrive.

It will open the window containing the AutoSaved files.

6. How to Recover Excel Files

6.1 Recover Excel File After Crash

Click on the File tab and then go to Open >> Recent >> Workbooks.
At the bottom, you will see Recover Unsaved Workbooks.

Click on this image to have a better view

Click on that and it will open a folder on your PC. You will get the crashed Excel files there.

6.2 Recover a Corrupted Excel File

Click on File >> Open >> Browse.

Write the corrupted file name in the File name box. Change the file type to All Files.
Select Open and Repair from the Open dropdown menu.

It will repair and open the corrupted file.

6.3 Recover a Previous Version of an Excel File

Click the File tab and select Info.
Click the Version History.

You will see the previous versions of that file.
You can recover your desired file.

6.4 How to Find Excel Backup Files

Go to File >> Open >> Recent in Excel.
In the Workbooks click on the Recover Unsaved Workbooks.

The Document Recovery You will find the backup files there.

7. How to Reduce Excel File Size

7.1 Reduce Excel File Size Without Opening It

We have an Excel file named Excel Files.

We will select the file and right-click on it.
Click Properties from the context menu.

In the Excel File Properties window, click Advanced.

Then, in the Advanced Attributes window, turn on the Compress contents to save disk space check box and click OK.

As a result, you will see the compressed file icon on the Excel file.

7.2 Reduce Excel File Size Without Deleting Data

Go to File >> Save As and change the file type to CSV UTF-8 (Comma Delimited) (*.csv).

You will see the file size reduced significantly.

7.3 How to Determine What is Causing Large Excel File Size

Click on the Review tab and select Workbook Statistics from the Proofing
It’s showing 3 sheets in Workbook Statistics. But only two sheets are visible. This means we have a hidden sheet in the workbook.

Right-click on any Sheet tab and select Unhide from the context menu.

You will see a dialog box with the title Unhide one or more sheets. Select the hidden sheets and Unhide them.

You can see the Sheet3 visible in the Sheet tab.

7.4 Compress Excel Files for Email

Select the file and right-click on it.
Choose Compress to ZIP file from the context menu.

You will get a zipped version of the same Excel file beside the main file.

8. How to Speed Up Excel

8.1 How to Make Excel Open Faster

Click the File tab and go to Options >> Advanced.
Select Use all processors in this computer.
This will make your Excel open faster.

8.2 How to Open Large Excel Files Without Crashing

Open Excel Options from File >> Options.
Click the Add-ins, choose COM Add-ins and Go.

Uncheck all the Add-ins and click OK.

It will open large files without crashing.

8.3 How to Stop Calculating Threads in Excel

Open Excel Options by clicking on File >> Options.
Go to Formulas, and in Calculation Options, choose Manual. This will stop calculating threads in Excel.

9. How to Encode Excel Files

9.1 Encode File to UTF-8 in Excel

Click the File tab and go to the Backstage View.
Select Save As and choose CSV UTF-8 (Comma Delimited) (*.csv) file format.
Click on Save and the file will be encoded.

9.2 Check Encoding of Excel Files

Go to the Save As option and you can see the file extension.
You will know the encoding of Excel files.

10. What to Do If Excel Files Are Not Opening?

10.1 Why Are My Excel Files Not Opening?

You have an Excel file.

Try to open it with Excel, it opens in Notepad.

Right-click on the file and choose Open with >> Excel from the context menu.

10.2 Excel File Open but Not Visible

Open the Excel file, and it does not show any data.

Go to the View tab and click on Window, it will show the hidden workbook.

10.3 Excel File Opens Blank Grey Screen

Go to File and open Excel Options.
In the Advanced >> General section, uncheck the Ignore other options that use Dynamic Data Exchange (DDE) option and click OK.

You can open the file resolving the gray screen issue.

11. How to Protect Your Excel Files

Click on the Review tab and choose Protect Sheet.

Put a password in the input box.

Reenter the password to confirm.

You can also Unprotect Sheet using the same way.

Note: We have used Excel for Microsoft 365 to prepare this article.

⏷Available File Types Supported in Excel
⏵Excel Files Format
⏵Text Format
⏵Other File Formats
⏵File Formats That Use Clipboard
⏵File Formats Not Supported in Excel
⏵Open or View Unsupported File Formats
⏷Overview of Excel File Extensions
⏵Difference Between Xlsx Vs Xls Format
⏵Difference Between Xlsx Vs Xlsb Format
⏵Check Excel File Extension
⏵Change Excel File Extension
⏵Save Macro Enabled File
⏷Open Excel Files
⏵Open Multiple Files in One Click
⏵Open Two Files Side By Side
⏷Combine/Merge Multiple Files
⏷Using Excel AutoSave
⏵Turn On AutoSave
⏵Change AutoSave Time
⏵Turn Off AutoSave
⏵Where AutoSave Files Are Stored
⏷Recover Excel Files
⏵Recover File After Crash
⏵Recover Corrupted File
⏵Recover Previous Version Of File
⏵Find Excel Backup Files
⏷Reduce Excel File Size
⏵Reduce Excel File Size Without Opening
⏵Reduce File Size Without Deleting Data
⏵Determine Cause of Large Excel File Size
⏵Compress Excel File for Email
⏷Speed Up Excel
⏵Make Excel Open Faster
⏵Open Large Files without Crashing
⏵Stop Calculating Threads in Excel
⏷Encode Excel Files
⏵Encode file to UTF-8 in Excel
⏵Check Encoding Of Excel File
⏷Excel Files Are Not Opening
⏵Excel Not Opening Files
⏵Excel File Open But Not Visible
⏵Excel File Opens Blank Grey Screen
⏷Protect Your Excel Files

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