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

UUE file extension

Uuencoded File

Encoded Files

ROM file extension

N64 Game ROM File

Game Files

PS file extension

PostScript File

Vector Image Files

CUE file extension

Cue Sheet File

Disk Image Files

VCXPROJ file extension

Visual C++ Project

Developer Files

IFF file extension

Interchange File Format

Audio Files

WSF file extension

Windows Script File

Executable Files

MOV file extension

Apple QuickTime Movie

Video Files

YUV file extension

YUV Encoded Image File

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

DLL file extension

Dynamic Link Library

System Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

XCODEPROJ file extension

Xcode Project

Developer Files

M file extension

Objective-C Implementation File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files