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

CSS file extension

Cascading Style Sheet

Web Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

M4A file extension

MPEG-4 Audio File

Audio Files

MAX file extension

3ds Max Scene File

3D Image Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PART file extension

Partially Downloaded File

Misc Files

PHP file extension

PHP Source Code File

Web Files

PIF file extension

Program Information File

Executable Files

PL file extension

Perl Script

Developer Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TIF file extension

Tagged Image File

Raster Image Files

TMP file extension

Temporary File

Backup Files

TTF file extension

TrueType Font

Font Files

WMA file extension

Windows Media Audio File

Audio Files

ZIPX file extension

Extended Zip File

Compressed Files