Common Windows file extensions

Windows file names have two parts; the file's name, then a period followed by the extension (suffix). The extension is a three- or four-letter abbreviation that signifies the file type. For example, in letter.docx the filename is letter and the extension is docx. Extensions are important because they tell your computer what icon to use for the file, and what application can open the file. For example, the doc extension tells your computer that the file is a Microsoft Word file.

If you want to open a MAC OS X file in Windows, you may need to add the extension to a MAC OS X file name so Windows can recognize it. For example, if you have a Word 6 MAC OS X document named letter that you want to open in Windows, you need to rename the file letter.docx so that Word in Windows will recognize and open the file.

List of File Extensions
Showing File Extensions
Searching File Extensions

Note: This list is by no means a complete and exhaustive list of file extensions. If the file extension you are using is not listed below, you may find the information by looking in the software manual or software application's Web site.

Note: If none of your file names have extensions, file extensions are hidden. See Showing File Extensions

File Extension File Type
.AIFF or .AIF Audio Interchange File Format
.AU Basic Audio
.AVI Multimedia Audio/Video
.BAT PC batch file
.BMP Windows BitMap
.CLASS or .JAVA Java files
.CSV Comma separated, variable length file (Open in Excel)
.CVS Canvas
.DBF dbase II, III, IV data
.DIF Data Interchange format
.DOC or .DOCX Microsoft Word for Windows/Word97
.EPS Encapsulated PostScript
.EXE PC Application
.FM3 Filemaker Pro databases (the numbers following represent the version #)
.GIF Graphics Interchange Format
.HQX Macintosh BinHex
.HTM or .HTML Web page source text
.JPG or JPEG JPEG graphic
.MAC MacPaint
.MAP Web page imagemap
.MDB MS Access database
.MID or .MIDI MIDI sound
.MOV or .QT QuickTime Audio/Video
.MTB or .MTW MiniTab
.PDF Acrobat -Portable document format
PageMaker (the numbers following represent the version #) P=publication, T=template
.PNG Portable Network Graphics
.PPT or .PPTX PowerPoint
.PSD Adobe PhotoShop
.PSP PaintShop Pro
.QXD QuarkXPress
.RA RealAudio
.RTF Rich Text Format
.SIT Stuffit Compressed Archive
.TAR UNIX TAR Compressed Archive
.TIF TIFF graphic
.TXT ASCII text (Mac text does not contain line feeds--use DOS Washer Utility to fix)
.WAV Windows sound
.WK3 Lotus 1-2-3 (the numbers following represent the version #)
.WKS MS Works
WPD or .WP5 WordPerfect (the numbers following represent the version #)
.XLS or .XLSX Excel spreadsheet
.ZIP PC Zip Compressed Archive

Showing File Extensions

If none of your file names have extensions, file extensions are hidden. To show file extensions:

1. In the File Explorer, click the "View" tab and select the check box next to "File name extensions." 

You can also follow these instructions, which will work for older versions of Windows. 
1. Click on the start menu and type "Show hidden files and folders," then press the enter key or select that option from the list of results.


2. In the "View" tab, make uncheck the option "Hide extensions for known file types." 


3. Click "Apply" then "OK".

Searching File Extensions

Sometimes you may want to search for all files of a certain type. For example, you may want to find a .pst file or a .mp3 file on your computer. Follow these steps to search for a file extension. 
1. Click on the Start menu or search bar and type "*" followed by the file extension you wish to search (ex. *.jpg) and hit the "Enter" key. 

2. Windows will now search for files ending in thte specified extension. 
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