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

AI file extension

Adobe Illustrator File

Vector Image Files

CGI file extension

Common Gateway Interface Script

Executable Files

CUR file extension

Windows Cursor

System Files

FLA file extension

Adobe Flash Animation

Developer Files

GADGET file extension

Windows Gadget

Executable Files

INI file extension

Windows Initialization File

Settings Files

M4A file extension

MPEG-4 Audio File

Audio Files

PHP file extension

PHP Source Code File

Web Files

PIF file extension

Program Information File

Executable Files

PRF file extension

Outlook Profile File

Settings Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

VCF file extension

vCard File

Data Files

ZIPX file extension

Extended Zip File

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files