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

AIF file extension

Audio Interchange File Format

Audio Files

AZW file extension

Amazon Kindle eBook File

eBook Files

BAT file extension

DOS Batch File

Executable Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

ICO file extension

Icon File

System Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

RSS file extension

Rich Site Summary

Web Files

SRT file extension

SubRip Subtitle File

Video Files

TEX file extension

LaTeX Source Document

Text Files

TIF file extension

Tagged Image File

Raster Image Files

TMP file extension

Temporary File

Backup Files

WMA file extension

Windows Media Audio File

Audio Files

XCODEPROJ file extension

Xcode Project

Developer Files