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

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

ODT file extension

OpenDocument Text Document

Text Files

TMP file extension

Temporary File

Backup Files

TORRENT file extension

BitTorrent File

Misc Files

DTD file extension

Document Type Definition File

Developer Files

HTML file extension

Hypertext Markup Language File

Web Files

FLV file extension

Flash Video File

Video Files

APK file extension

Android Package File

Executable Files

PPS file extension

PowerPoint Slide Show

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files

MP3 file extension

MP3 Audio File

Audio Files

PAGES file extension

Pages Document

Text Files

DRV file extension

Device Driver

System Files

TARGZ file extension

Compressed Tarball File

Compressed Files