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

AIF file extension

Audio Interchange File Format

Audio Files

CPP file extension

C++ Source Code File

Developer Files

DDS file extension

DirectDraw Surface

Raster Image Files

EXE file extension

Windows Executable File

Executable Files

JPG file extension

JPEG Image

Raster Image Files

LOG file extension

Log File

Text Files

M4A file extension

MPEG-4 Audio File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

PAGES file extension

Pages Document

Text Files

SWF file extension

Shockwave Flash Movie

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

TIF file extension

Tagged Image File

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

ZIP file extension

Zipped File

Compressed Files