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

ASF file extension

Advanced Systems Format File

Video Files

JAR file extension

Java Archive File

Executable Files

JSP file extension

Java Server Page

Web Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MID file extension

MIDI File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

MPA file extension

MPEG-2 Audio File

Audio Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

ROM file extension

N64 Game ROM File

Game Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SYS file extension

Windows System File

System Files

TAR file extension

Consolidated Unix File Archive

Data Files

TXT file extension

Plain Text File

Text Files

VCD file extension

Virtual CD

Disk Image Files