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

AVI file extension

Audio Video Interleave File

Video Files

BAT file extension

DOS Batch File

Executable Files

CFG file extension

Configuration File

Settings Files

DDS file extension

DirectDraw Surface

Raster Image Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

EPUB file extension

Open eBook File

eBook Files

EXE file extension

Windows Executable File

Executable Files

M file extension

Objective-C Implementation File

Developer Files

M4A file extension

MPEG-4 Audio File

Audio Files

PDF file extension

Portable Document Format File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

TAR file extension

Consolidated Unix File Archive

Data Files

WAV file extension

WAVE Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files