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
.P65 .T65	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.