File extensions / file formats

Each file has an extension usually formed from three characters after the name of the file and a period (ex. filename.txt). Usually the operating system on a computer hides the extensions of the files for security reasons but it can be set to be viewable in case someone wants to see the extensions of the files. The file extension is associated with the program it can be accessed with, it simply tells what application is being used or edited with or what type of system file it is.

A list of common file extensions:

ace     Archive, compressed
amr     Compressed audio
arj      Archive, compressed
asp     ASP script, used on web pages
avi      Audio Video Interleave movie or video
bak     Backup
bat     Batch file (executable)
bmp    Windows Bitmap image
cab     Windows Cabinet Compressed Archive
cdr     CorelDRAW vector image
css     Cascading Style Sheets
dat     Text or binary data file
dbf     Database file
doc     Microsoft Office Word document
exe     Executable file
gif      Graphics interchange file format
htm     Web page – HTML file
html    Hypertext Markup Language – Web page file
ico      Icon file
ini       Text configuration file
iso      CD/DVD ISO binary image file
jar      Compressed archive file package for Java classes and data
jpeg    JPEG image, picture file format
jpg      JPEG bitmap image file format
js       JavaScript file
lnk      Windows Shortcut
mdb    Microsoft Access database
mp3    Compressed audio, music file
mp4    MPEG-4 file format
mpg    MPEG 1 video or movie file format
msi     Microsoft Windows Installer installation package file
pdf     Portable document format: Adobe Acrobat File
php     PHP script, page
png     Portable (Public) Network Graphic
pps     Microsoft PowerPoint Slideshow
psd     Adobe Photoshop graphics
rar      RAR compressed archive – backup file
rss      Really Simple Syndication – RSS file format
rtf      Rich Text Format document
swf     ShockWave Flash, Animated vector format for the Internet
sys     System file
tif       Aldus Tagged Image File Format (TIFF) bitmap image
tmp     Temporary file
txt      Common text file
vxd     Microsoft Windows virtual device driver, 32 bit
wav    WAVe PCM Sound, standard Windows sound format
xls      Microsoft Office Excel spreadsheet
xml     XML document
zip      Compressed ZIP archive file and compressed folder