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

ACCDB file extension

Access 2007 Database File

Database Files

CLASS file extension

Java Class File

Developer Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

KML file extension

Keyhole Markup Language File

GIS Files

KMZ file extension

Google Earth Placemark File

GIS Files

M3U file extension

Media Playlist File

Audio Files

M4A file extension

MPEG-4 Audio File

Audio Files

ODT file extension

OpenDocument Text Document

Text Files

PPS file extension

PowerPoint Slide Show

Data Files

SRT file extension

SubRip Subtitle File

Video Files

UUE file extension

Uuencoded File

Encoded Files

VCXPROJ file extension

Visual C++ Project

Developer Files

VOB file extension

DVD Video Object File

Video Files

XCODEPROJ file extension

Xcode Project

Developer Files

YUV file extension

YUV Encoded Image File

Raster Image Files