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

BAT file extension

DOS Batch File

Executable Files

CPP file extension

C++ Source Code File

Developer Files

DAT file extension

Data File

Data Files

DOC file extension

Microsoft Word Document

Text Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GAM file extension

Saved Game File

Game Files

ISO file extension

Disc Image File

Disk Image Files

MAX file extension

3ds Max Scene File

3D Image Files

MDF file extension

Media Disc Image File

Disk Image Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

SDF file extension

Standard Data File

Data Files

TMP file extension

Temporary File

Backup Files

XCODEPROJ file extension

Xcode Project

Developer Files

YUV file extension

YUV Encoded Image File

Raster Image Files