Common file types and how to open them

.aif or .aiff  A music or sound file (aiff = "Audio Interchange File Format") commonly found in the Internet.  Open in Windows Media Player. May also be opened in RealOne Player or WinAmp if you have them on your computer.

.au  A music or sound file format commonly found in the Internet.  Open in Windows Media Player. May also be opened in RealOne Player or WinAmp if you have them on your computer.

.bmp  A digital image in Windows Bit Map format.    Open in Windows Picture and FAX Viewer, Imaging, Paint, Photo Editing Software or any other photo viewing or editing software you may have on your computer. Uncompressed.

.csv  "Comma Separated Values".  A table of numeric or text entries in which the columns are separated by commas.  Open in Notepad, WordPad, any spreadheet or word processor program. A spreadsheet program will display the data in columns, interpreting the commas to be column separators.

.doc  A word processor file.  Open in Word, WordPad, Word, Word Viewer, Open Office, or any word processor. See Note.

.dll   A dynamic link library file, a fragment of programming code.  For the computer's use only - not openable or readable by humans.

.eml  A saved e-mail.  Open in your e-mail program.

.est   A map saved from Microsoft Streets and Trips.   Must have that program installed to open it.

.exe  An executable program  file.   Might be a program, an installer, or a stand-alone slideshow.  To open it (i.e. run it), right-click the file and select Open. Caution: an exe file may contain viruses. Before you run an unknown exe file, scan it for viruses first (Right-click on the file and select Scan with Norton AntiVirus)

.gif  A graphic file type used for logos, cartoons, and line drawings (gif = "Graphic Interchange Format").   Open in Windows Picture and FAX Viewer, Imaging, Paint, Photo Editing Software, Internet Explorer, Netscape, or any other photo viewing or editing software you may have installed on your computer.

.hqx  A Macintosh text-encoded binary file (similar to a ZIP file).   Open in WinZip or Aladdin Systems Stuffit for Windows. Downloaded from http://www.stuffit.com.

.htm or .html  A Web page (text part only; the graphics are stored in separate graphic files).  Open for viewing in Internet Explorer or Netscape. Open for editing in NotePad, WordPad, any Web editor (like Front Page) or any word processor. (html = "HyperText Markup Language").

.ini  "Initialization Information" file.  A text file containing settings and other information for use by a program.  Can be opened with Notepad.  An example is Picasa.ini, used by Picasa.

.jpg  A digital photograph (jpg = "Joint Photographic Group").  Open in Windows Picture and FAX Viewer, Imaging, Paint, Photo Editing Software, Internet Explorer, Netscape, or any other photo viewing or editing software you may have on your computer.

.lbl  A label (e.g. for a CD disk or other label type) created in Print Shop. Open in Print Shop. 

.LDIF   Data Interchange Format file.  Used for transferring your address book to a new computer or mail program.  

.mid  A music file in MIDI format (MIDI = "Music Instrument Digital Interface").  To play, open in Windows Media Player. To edit, open in a MIDI editor such as Sweet MIDI Player (downloadable from http://www.ronimusic.com/swmipl.htm) .  

.mov  A digital video clip in Quicktime format. Open in Quicktime Player. 

.mp3  A compressed music or sound file.  This is a compressed format that occupies about 1/20th of the disk space as the equivalent WAV file.  Commonly found in the Internet. Open in Windows Media Player. May also be opened in RealOne Player or MusicMatch, if you have them installed on your computer.

.mpg  A digital video clip; mpg = "Motion Picture Group".  Open in Windows Media Player. 

.pdf  A formatted document ready for printing; PDF = "Portable Document Format".  To view, open in Adobe Acrobat Reader.  The latest version of the free Adobe Acrobat Reader can be downloaded from http://www.adobe.com/.

.png  Portable Network Graphic.  A replacement for the older GIF graphic format for bitmap (raster) graphics (see above).  Supports more colors than GIF. Opens in most graphic programs.

.ppt  A Microsoft Powerpoint presentation.  Open in Microsoft Powerpoint or Powerpoint Player. You can download the free Powerpoint Viewer from http://office.microsoft.com/.

.psp  This could be either a Print Shop document or a Paint Shop Pro image (there is a conflict in the use of the psp extension).  Open in either Print Shop or Paint Shop Pro. 

.ram or .ra  Real Audio file, commonly used for Internet audio. Open in ReadOne Player.  Download player from http://www.real.com/.

.rtf  "Rich Text Format", a generic formatted text format.  Open in WordPad, Word, Word Viewer, or any word processor.

.slk  "Symbolic Link" format.  A generic spreadsheet format. Open in Microsoft Excel or any other spreadsheet.\

.sxw  Native format of a word processor document saved from Open Office (a free replacment for Microsoft Office Suite; see openoffice.org)

.tif or tiff  "Tagged Image File format".  Open in Windows Picture and FAX Viewer, Paint, or other photo viewing or editing software you may have on your computer.

.txt  A plain text file (just the words - no fonts, formatting or graphics).  To view or edit, open in NotePad, WordPad, MS Word.

.wav  An uncompressed music or sound  file.  Open in Windows Media Player.

.wmv  A digital video file in Windows Media Video format.  Open in Windows Media Player.

.wps  Microsoft Works word processor document.  Open in Microsoft Works.

.xlr  Microsoft Works spreadsheet document.  Open in Microsoft Works.

.xls  Microsoft Excel spreadsheet document.  Open in Microsoft Excel or Excel Viewer.  See Note.

.zip  A compressed file archive (containing a mixture of various file types and folders).  To open it, right-click the file and select Extract All....

Note 1: Freeware viewer programs for Microsoft applications (e.g. Word, Excel, and Powerpoint) may be downloaded from http://office.microsoft.com/.
Note 2: For a comprehensive list of file extensions, see http://filext.com/
Tom O'Haver, November 2005