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

CER file extension

Internet Security Certificate

Web Files

CUE file extension

Cue Sheet File

Disk Image Files

DNG file extension

Digital Negative Image File

Camera Raw Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GZ file extension

Gnu Zipped Archive

Compressed Files

LNK file extension

Windows File Shortcut

System Files

M file extension

Objective-C Implementation File

Developer Files

PHP file extension

PHP Source Code File

Web Files

PIF file extension

Program Information File

Executable Files

TGA file extension

Targa Graphic

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files

WMA file extension

Windows Media Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files

3G2 file extension

3GPP2 Multimedia File

Video Files