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

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DDS file extension

DirectDraw Surface

Raster Image Files

EPUB file extension

Open eBook File

eBook Files

GZ file extension

Gnu Zipped Archive

Compressed Files

HTM file extension

Hypertext Markup Language File

Web Files

IBOOKS file extension

Multi-Touch iBook

Data Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MSI file extension

Windows Installer Package

Misc Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

ROM file extension

N64 Game ROM File

Game Files

TAR file extension

Consolidated Unix File Archive

Data Files

VCF file extension

vCard File

Data Files

VOB file extension

DVD Video Object File

Video Files

WPD file extension

WordPerfect Document

Text Files