Written by
Yuri ZhangSummary: File name extension/file extension, is the suffix at the end of a file name that indicates the file format. This article lists common extensions and what we should know to discern them for Mac and Windows.
File name extensions implicate file types. How many file name extensions are in the world? The answer is hundreds of thousands, with databases and sources listing over 30,000 file types.
Common file extensions are easily recognized, such as .txt, .jpg, .docx, and .mp3. There is no exact number of file extensions, as new file extensions are constantly being created with new software and technologies.
Note 1: For instance, what do file name extensions .yxmd represent? Many software programs or specialized applications, like Alteryx, AutoCAD, or Photoshop, use their own unique file extensions. The .yxmd specifically refers to a workflow document created in Alteryx Designer, which contains the steps and configuration for processing data.
Note 2: File name extension helps determine which kind of programs can open it. The extension is associated with specific software or applications that can read, edit, or run the file.
Common file extensions meaning for Mac and Windows
It's necessary to know Windows cannot open .dmg files, as they are specific to macOS, and macOS cannot open .exe files designed for Windows. Still, you can see from the table that some common extensions can be used in both Mac and Windows OS:
| File Type | Windows File Extensions | macOS File Extensions |
| Text Documents | .txt (Text File) | .txt (Text File) |
| .doc / .docx (Microsoft Word) | .pages (Apple Pages) | |
| .rtf (Rich Text Format) | .rtf (Rich Text Format) | |
| .pdf (Portable Document Format) | .pdf (Portable Document Format) | |
| Image Files | .jpg / .jpeg (JPEG Image) | .jpg / .jpeg (JPEG Image) |
| .png (Portable Network Graphics) | .png (Portable Network Graphics) | |
| .bmp (Bitmap Image) | .bmp (Bitmap Image) | |
| .gif (Graphics Interchange Format) | .gif (Graphics Interchange Format) | |
| .tiff (Tagged Image File Format) | .tiff (Tagged Image File Format) | |
| .ico (Icon File) | .icns (Icon File) | |
| Audio Files | .mp3 (MP3 Audio) | .mp3 (MP3 Audio) |
| .wav (Waveform Audio) | .m4a (Apple Lossless Audio Codec) | |
| .flac (Free Lossless Audio Codec) | .aac (Advanced Audio Codec) | |
| Video Files | .mp4 (MPEG-4 Video) | .mp4 (MPEG-4 Video) |
| .avi (Audio Video Interleave) | .mov (QuickTime Movie) | |
| .wmv (Windows Media Video) | .mkv (Matroska Video) | |
| .mkv (Matroska Video) | .webm (WebM Video) | |
| Compressed Files | .zip (ZIP Archive) | .zip (ZIP Archive) |
| .rar (RAR Archive) | .dmg (Disk Image, Mac-specific) | |
| .7z (7-Zip Archive) | .tar.gz (Compressed Archive) | |
| .tar (Tape Archive) | .sit (StuffIt Archive) | |
| Executable Files | .exe (Executable Program) | .app (Mac Application) |
| .bat (Batch File) | .command (Shell Script) | |
| .msi (Microsoft Installer) | .pkg (Package Installer) | |
| System Files | .dll (Dynamic Link Library) | .kext (Kernel Extension) |
| .sys (System File) | .plist (Property List) | |
| .ini (Configuration File) | .app (App Bundle) | |
| Backup Files | .bak (Backup File) | .backup (Backup File) |
Bonus tip: Be wary of dealing with system files
As a reminder, I want to warn you: when researching and installing multiple software or gadgets on your PC, always be cautious and do not delete them. Here's a real-life experience:
I once accidentally deleted system files that required administrative permissions, which caused some issues with my system. Some processes began to run inefficiently, and my laptop keyboard stopped working and crashed.
The files you shouldn't delete in your operating system are often marked as protected or system files. These files are critical for the proper functioning of your OS, and deleting them can lead to significant system instability.
Note: Usually, for Windows, .dll/.sys/.exe/.ini files/.bat files are protected system files. For macOS, .kext/.plist/.app/.dmg files are protected system files. These files are typically hidden or require admin permissions to access or modify.
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File name extensions for Excel
Here are the file name extensions commonly associated with Microsoft Excel for both Windows and macOS. This deepens understanding of branches of file name extensions, they always change as time goes by or are not invariable.
- .xls – Older Excel file format (Excel 97-2003).
- .xlsx – Modern Excel workbook file format (Excel 2007 and later), based on Open XML.
- .xlsm – Excel workbook with macros (Excel 2007 and later), allows VBA scripting.
- .xltx – Excel template file without macros (Open XML format).
- .xltm – Excel template file with macros.
- .xlsb – Excel Binary Workbook, a faster and more compact binary format.
- .csv – Comma-separated values file used for importing/exporting data.
- .txt – Tab-delimited text file.
- .prn – Space-delimited text file.
Final thought
Some file extensions are platform-specific (e.g., .app for macOS, .exe for Windows) or used in specific industries (e.g., .dmg for macOS disk images, .xlsx for Excel spreadsheets).
In the case of Finder on macOS and Windows Explorer in Windows, they identify and help manage file extensions by allowing users to see the full name and extension of files when browsing their directories, making it easier to distinguish file types for better organization and opening with the appropriate apps.
Also read How to display file name extensions on Windows 11/10/8/7
For more file name extension knowledge, share and comment!