The file extension is the alpha-numeric character or characters
to the right of the dot (or period) in the file name. All file
names end with the file extension. The extension indicates the
format that the file is written in. When a file is saved, the
computer operator provides the file name and the program used
provides the file extension, unless the user chooses another
By default, Windows hides many file extensions for known
file types. To see the extensions for all file types, the user
must uncheck the "Hide file extensions for known file types"
setting in the Folder Options window. Click on the View tab to
see this option.
(Caution: if you change the setting to view extensions, you
must make sure that you always retain the same extensions when
you change the name of a file.)
It is often helpful to see the file type so that the computer
user can identify the program that was used to create the file.
Knowing what program was used to create the file is helpful in
knowing what program to use to display the file contents. For
example, you may receive an attachment to an e-mail message that
contains the following file name: filename.ppt. When you try
to display this file, you cannot open it. You wonder why you
cannot see the contents of this file. If you could find out what
program was used to create this file, you would have a better
idea of what program you would need in your computer to view
it. In the example file shown above, Microsoft PowerPoint program
in MS Office was used to create the file. In order to view this
file, you would need MS PowerPoint program or MS PowerPoint Reader
installed in your computer. Knowing what program was used to
create a .ppt file helps you to know what you need in your computer
to view or work with the file.
The following Web sites below can help you find the meaning
of the extension and the possible program that was used to create
the file. With this information, you can determine if you have
a program that can display the file or if you need to acquire
and install a program.
If you do a search on "file extension" in Google
for example, you will find many Web sites that help identify
a given file extension. Here are some sites that can help: