File Extensions Dictionary

Find a file extension by Alphabetical Index:
  (For example, to look up .exe  click on E.)
      [A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Find a file extension by File Type:
   

A
.asp Active Server page. You may notice this extension in the address bar of websites you visit. Essentially, ASP code is a tool from MicroSoft used to add some fancy features to web pages. ASPs are server-generated pages which can call other programs to do things like access databases, and serve different pages to different browsers
.avi A Window video file. (Audio Video Interleave file)
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
B
.bak A backup file for the operating system.
.bat Batch file. Commonly used to store system software information. Manufacturers often intall batch files instead of supplying an operating system cd. These are crucial files and should never be deleted.
.bin MacBinary Encoded File. This file type requires Stuffit Expander for Macintosh computers.
.bkp A backup file extension used by some software applications.
.bmp Bitmap image file. This file type is common for desktop backgrounds.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
C
.cgi Common Gateway Interface script. This file extension is common in internet addresses. CGI involves a method of transferring data from web pages to scripts running on a web server and back again.
.com Command file. An executable application or program. (Be careful, since many viruses are spread as .com files)
.csv Comma-Separated Values. Most often generated by database or spreadsheet programs in order to present tabular data in a flat file. Each row in the file represents a row in the original data table; the values in adjacent columns are separated by a comma.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
D
.dat Data file. A basic flat file of data, almost entirely free of structure. Can be opened by many software applications including text editor programs. (However when a .dat file exceeds a few megabytes in size, it may be too big for a text editor to open.)
.dic A Dictionary file. Usually specific to a MicroSoft application (e.g. MS-Word).
.dll Dynamic Link Library file. A DLL is a collection of small programs, used individually by a larger program that is running in the computer. The purpose of such a small program can be to let the larger program communicate with a specific device such as a printer or scanner. (DLL files that support specific device operation are known as device drivers.)
.doc MicroSoft Word (MS-Word) file. Opens automatically with MS-Word. Be careful of version compatibility issues when working on different computers.
.dxf An AutoCAD file. This program is used by architects to create floorplans and blueprints.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
E - F
.exe An executable file - an application or program; downloading and double-clicking on a .exe file will cause it to run.
.E00 ArcInfo Coverage Export File. Used for Geospatial data.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
G
.gif A standard image file. (Graphic Interchange File) Can be opened with any graphics viewer or editor, or any browser.
.gz or .gzip GNU zip file. A popular format for compressing a single large data file. Used on the Unix platform (not Windows or Macintosh).
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
H
.hqx ASCII-encoded binary file. A common format on the internet for files for Macs.
.htm .htm is synonymous but not identical to .html   Both are commonly known as HTML files, which stands for "Hyper Text Mark-up Language". For today's internet user, .htm and .html are equivalent. .htm is left over from the days when Windows did not support four-letter extensions for their files. Now all standard machines accept .html. But be careful: the two file extensions are equivalent in purpose, but not in reality. Two files called index.htm and index.html will be two distinct files. One must still be careful when opening and saving files written in HTML.
.html Hyper Text Mark-up Language. This file is a simple "web page", a file that can be viewed by any browser (such as Netscape or Intenet Explorer). One key property of HTML is the use of hyper text links, which allows the user to jump between sections and across pages in internet documents.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
I
.ini Initialization file. Contains the initial configuration settings of a specific program.
.ivt Beyond 20/20 file. This program is a statistical browser for viewing tabular data.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
J - L
.jpg or .jpeg A standard image file. (Joint Photography Experts Group) Can be opened with any graphics viewer or editor, or any browser.
.jsp Java Server page. You may notice this extension in the address bar of websites you visit. JSP code helps add some fancy features to web pages, and they work well across all kinds of computers. ASPs are server-generated pages which can call other programs to do things like access databases, and serve different pages to different browsers
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
M - O
.mdb MS-Access file. A simple database file. Opens with MS-Access.
.mif MapInfo Interchange format. Geospatial data file for MapInfo software.
.mp3 A highly-compressed file format. This file format is most used for music files and movies.
.mpg or .mpeg The most popular file format for movies. A compressed file format.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
P - Q
.pdf Portable Document Format. PDF files give the user a non-modifiable copy of a document. Opens with Adobe Acrobat Viewer; can be edited with Adobe Acrobat.
.pic A Bitmap graphic file. Produced by the following softwares: PC Paint, Lotus picture, or Mac PICT Drawing.
.png Portable (Public) Network Graphic file. An alternative to the .gif format.
.pps MicroSoft Powerpoint slide show presentation. Double-clicking on this file will cause the slide show to run. (Your entire screen will go blank and soon be filled by the first slide. Left-click with your mouse to progress through the slides; hit Escape on your keyboard at any time to exit.) .pps files are often distributed by e-mail.
.ppt MicroSoft Powerpoint file. Opens with and is created with MicroSoft Powerpoint. Opening it allows you to edit the slide show presentation.
.ps PostScript file. Similar to PDF, this format allows a document to be viewed and printed but not edited. Can be printed using GhostScript, GhostWriter, or GSview software.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page

R
.ra RealAudio file. A popular sound file format. For use with RealAudio player.
.rtf Rich text file. Can be opened with any text editor program such as Notepad, Wordpad, MS-Word. .rtf format permits some formatting of the document's style, such as bold text, different font sizes and styles.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
S
.sas SAS file. SAS is a statistical analysis software.
.sea Self-Extracting Archive file. Compressed archived file for the Macintosh. Can be read on any platform with StuffIt Expander software.
.sgml Standard Generalized Mark-up Language. International standard for electronic presentation of texts. Largely used by the publishing industry and digital libraries.
.shp Shape file. Used for Geospatial data, with ArcView software.
.shtm or .shtml A form of .sgml  Used specifically for web page editing.
.sit StuffIt Compressed Archive file. Compressed archived file for the Macintosh.
.sps or .spss SPSS file. SPSS is a statistical analysis software.
.sys System driver file. Can be used by the whole operating system or by a single application.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]
Back To Top of Page
T - U
.tab A tabular data file. Data columns are separated by tabs. This file format is designed for numeric data sets.
.tar Tape Archive file. A UNIX file format.  tar files are often further compressed, and therefore may be found with the extension .tar.z or .tar.gz
.tex Text file format, most often used for scientific text editing. Generating a .tex format document requires TeX or LaTeX software. May be viewed with Scientific Viewer software.
.tif or .tiff Tagged Image File Format. A lesser-known image file type. Can be opened with any graphics viewer or editor, or any browser. This file type is most commonly encountered in using Adobe Photoshop.
.tmp Temporary file. Used by the operating system to store current working information and data.
.txt Text file. Can be opened with any text editor program such as Notepad, Wordpad, MS-Word. .txt format permits no formatting of the document, only spaces and line breaks.
.uue UUencoding file. 7-bit ASCII encoding for binary files.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]


Back To Top of Page
V
.vdo VDOscript file. Video file format; its player software is no longer available.
.viv VivoActive file. Video file used with VivoPlayer software. This format is known for mediocre image quality but very compact files.
.vts Formula One file. This spreadsheet program is an alternative to MS-Excel.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]


Back To Top of Page
W
.wav A popular sound file format.
.wp WordPerfect (WP) file. May be opened with WordPerfect or MS-Word.
.wp51 WordPerfect version 5.1 (WP51) file. A file with this extension probably dates from the early 1990s. May be opened with WordPerfect (version 5.1 or higher) or MS-Word.
.wpd WordPerfect (WP) file. May be opened with WordPerfect or MS-Word.
.wri Windows 3.1 Write file. A formatted word-processing document. Can be opened with any text editor program such as Notepad, Wordpad, MS-Word. .rtf format permits some formatting of the document's style, such as bold text, different font sizes and styles.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]


Back To Top of Page

X - Y
.xls MicroSoft Excel (MS-Excel) spreadsheet. Can also be generated by a database.
.xml Extensible Mark-up Language. A language used to write web pages; similar to HTML, but newer, more complex, and with extra capabilities.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]


Back To Top of Page
Z
.z Compressed file, generated by a computer running the UNIX operating system. Can be extracted using WinZip software (95 or later).
.zip A compressed file package. Can be unzipped by "WinZip" software. A "zipped" package of one or more files can significantly reduce the size in bytes; this method is therefore very popular for transmitting files. The WinZip software is available for free download on the internet, and is also used to create zipped file packages.
[A|B|C|D|E-F|G|H|I|J-L|M-O|P-Q|R|S|T-U|V|W|X-Y|Z]


Back To Top of Page
Prepared by Christine Rogers & Anastassia Khouri
Last updated: March 11, 2002  (CR)
©  EDRS - McGill University