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

DXF file extension

Drawing Exchange Format File

CAD Files

H file extension

C/C++/Objective-C Header File

Developer Files

M4A file extension

MPEG-4 Audio File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

PL file extension

Perl Script

Developer Files

RM file extension

Real Media File

Video Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

VCF file extension

vCard File

Data Files

VCXPROJ file extension

Visual C++ Project

Developer Files

XCODEPROJ file extension

Xcode Project

Developer Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files

3GP file extension

3GPP Multimedia File

Video Files