File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

ACCDB file extension

Access 2007 Database File

Database Files

BAT file extension

DOS Batch File

Executable Files

C file extension

C/C++ Source Code File

Developer Files

CLASS file extension

Java Class File

Developer Files

COM file extension

DOS Command File

Executable Files

GADGET file extension

Windows Gadget

Executable Files

JSP file extension

Java Server Page

Web Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MDB file extension

Microsoft Access Database

Database Files

PL file extension

Perl Script

Developer Files

SLN file extension

Visual Studio Solution File

Developer Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TORRENT file extension

BitTorrent File

Misc Files

UUE file extension

Uuencoded File

Encoded Files

YUV file extension

YUV Encoded Image File

Raster Image Files