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

BMP file extension

Bitmap Image File

Raster Image Files

CUE file extension

Cue Sheet File

Disk Image Files

JSP file extension

Java Server Page

Web Files

M3U file extension

Media Playlist File

Audio Files

MP4 file extension

MPEG-4 Video File

Video Files

MPG file extension

MPEG Video File

Video Files

MSG file extension

Outlook Mail Message

Text Files

ODT file extension

OpenDocument Text Document

Text Files

PDF file extension

Portable Document Format File

Layout Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

SLN file extension

Visual Studio Solution File

Developer Files

SRT file extension

SubRip Subtitle File

Video Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TMP file extension

Temporary File

Backup Files

VCXPROJ file extension

Visual C++ Project

Developer Files