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

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

WAV file extension

WAVE Audio File

Audio Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

3DS file extension

3D Studio Scene

3D Image Files

BIN file extension

Binary Disc Image

Disk Image Files

TORRENT file extension

BitTorrent File

Misc Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

LOG file extension

Log File

Text Files

SWF file extension

Shockwave Flash Movie

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

SAV file extension

Saved Game

Game Files

3G2 file extension

3GPP2 Multimedia File

Video Files

HTM file extension

Hypertext Markup Language File

Web Files

ISO file extension

Disc Image File

Disk Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files