Common Filename Extensions


Filenames (e.g.: song.mp3, letter.doc, logo.gif) consiste of three parts:

  • the name (e.g.: song, letter, logo)
  • a period . character
  • the extension (e.g.: mp3, doc, gif)

The following tables identifies the common filename extensions that are used in MS-DOS, in Windows, and on the internet.

Extension Association
ai Adobe Illustrator graphics file. See: Adobe Illustrator.
asa Active Server file. See: Microsoft FrontPage.
avi Audio Video Interleave file.
bak Backup file.
bat Batch file.
bmp Windows bitmap graphics file.
css Cascading Style Sheet file. Used to format webpages.
csv Comma-Separated Values file. A generic way of storing a table of data, one record per line, each field value separated by a comma and enclosed in quotation marks (if needed). See: Microsoft Excel.
db Database file.
dll Dynamic Link Library. Provides functionality that Windows programs can call upon. Part of the Windows operating system and also included with some programs.
doc Microsoft Word file. See: Microsoft Word.
exe Executable file. An MS-DOS program or a Windows application.
gif Graphic Interchange Format file. Used for simple graphics such as webpage buttons. Not suitable for photogphs since limited to 256 unique colors. See: jpg and jpeg extensions.
gz Gzip Compressed Archive file. See: Linux gzip compression program.
ico Windows Icon file. Graphics file used to visually show a file's extension; for example, the icon for a Microsoft Word document (.pdf) looks different than the icon for an Adobe PDF file (.pdf). Also used in web browser's Bookmarks menu (favicon.ico).
ini Initialization / Configuration file. Contains program configuration information. The file is typically a text file; however, it should not be edited manually.
jpeg JPEG/JIFF Image graphics file. Used for high quality images such as photographs. Since uses a "lossy" data compression, repeatedly opening/editing/saving an image will degrade the image quality. See: png which is a lossless image format.
jpg Same as jpeg. See: jpeg extension above.
js JavaScript file. JavaScript is a programming language used on webpages.
m3v MPEG-3 Video file.
m4a MPEG-4 Audio file. See: Apple iTunes.
m4v MPEG-4 Video file.
mdb Microsoft Access database file. See: Microsoft Access.
mid Musical Instrument Digital Interface (MIDI) file. Used with electronic musical instruments.
mov QuickTime video (Apple Inc.). See: Apple QuickTime.
mp3 MPEG Audio Stream, Layer III. See: MP3 music players.
mpeg MPEG Movie.
mpg MPEG Movie. See: mpeg above.
msi Windows Installer file (Microsoft Corporation). When you install a new application, it typically comes packaged in an msi file.
pdf Acrobat Portable Document Format. See: Adobe Acrobat, Adobe Reader
pl PERL program file. Used mostly on websites; however, can also be used as a scripting language on MS-DOS/Windows. See: Perl Programming Language, ActivePerl (for Windows).
png Portable Network Graphics is a bitmapped image format that uses lossless data compression. Unlike jpg files, you can open/edit/save files repeatedly without degrading the image.
psd Adobe Photoshop file. Graphics file format. See: Adobe Photoshop.
psp PhotoShop file. Graphics file format. See: Corel PhotoShop.
rar RAR Compressed Archive (RarLab). See: WinRAR (Windows and MS-DOS).
rm RealMedia Streaming Media file (RealNetworks, Inc.). See: RealPlayer.
sql Structured Query Language data file. Used to store SQL database data and command. See: SQL database computer language.
sqlite SQLite database file. See: SQLite Expert (Windows program), sqlite3.exe (MS-DOS).
swf Shockwave Flash file. Used on webpages for animations and video. See: Adobe Flash, Alligator Flash Designer.
tar tar ("Tape Archive") archive file format, commonly referred to as a "tarball" archive file. Typically used on Linux to archive files into one file. Does not compress the data; however, does preserve directory structure and file attributes. A .tar.gz (or .tgz) file is a .tar file compressed with the gzip compression program. See: WinZip.
tar.gz tar archive file that has been compressed with gzip. The extension .tgz is short for .tar.gz. See: tar above, and WinZip.
temp Typically used to indicate a temporary file.
tgz tar archive file that has been compressed with gzip. The extension .tgz is short for .tar.gz. See: tar above, and WinZip.
Tagged Image File Format is a file format used for storing images, including photographs and line art.
tmp Typically used to indicate a temporary file.
txt Text file. Open with Windows Notepad text editor.
xls Spreadsheet file format. See: Microsoft Excel.
xml XML (Extensible Markup Language) fle format. See: XML.
xsd XSD (XML Schema Definition) file format. See: XML.
wav Waveform Audio file format. Used to store uncompressed audio.
wma Windows Media Audio (WMA) is a digital audio file format. See: Windows Media Player.
wmv Windows Media Video (WMV) is a compressed video file format. See: Windows Media Player.
zip ZIP file format is a data compression and archive format. See: WinZip.

Related Commands:

Displays or modifies file extension associations.