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

ACCDB file extension

Access 2007 Database File

Database Files

AI file extension

Adobe Illustrator File

Vector Image Files

ASF file extension

Advanced Systems Format File

Video Files

ASX file extension

Microsoft ASF Redirector File

Video Files

EPUB file extension

Open eBook File

eBook Files

GADGET file extension

Windows Gadget

Executable Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MID file extension

MIDI File

Audio Files

NES file extension

Nintendo (NES) ROM File

Game Files

PNG file extension

Portable Network Graphic

Raster Image Files

SH file extension

Bash Shell Script

Developer Files

TAR file extension

Consolidated Unix File Archive

Data Files

XCODEPROJ file extension

Xcode Project

Developer Files

ZIP file extension

Zipped File

Compressed Files

3G2 file extension

3GPP2 Multimedia File

Video Files