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

BAK file extension

Backup File

Backup Files

C file extension

C/C++ Source Code File

Developer Files

DEB file extension

Debian Software Package

Compressed Files

DOC file extension

Microsoft Word Document

Text Files

DOC# file extension

Microsoft Word Document

Text Files

DXF file extension

Drawing Exchange Format File

CAD Files

FLV file extension

Flash Video File

Video Files

H file extension

C/C++/Objective-C Header File

Developer Files

ICS file extension

iCalendar File

Misc Files

MP4 file extension

MPEG-4 Video File

Video Files

PIF file extension

Program Information File

Executable Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TTF file extension

TrueType Font

Font Files

ZIP file extension

Zipped File

Compressed Files

3GP file extension

3GPP Multimedia File

Video Files