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

ASF file extension

Advanced Systems Format File

Video Files

BAK file extension

Backup File

Backup Files

CFM file extension

ColdFusion Markup File

Web Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

EPUB file extension

Open eBook File

eBook Files

GZ file extension

Gnu Zipped Archive

Compressed Files

ICS file extension

iCalendar File

Misc Files

KEY file extension

Keynote Presentation

Data Files

LNK file extension

Windows File Shortcut

System Files

MSI file extension

Windows Installer Package

Misc Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WMA file extension

Windows Media Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files

XCODEPROJ file extension

Xcode Project

Developer Files

3DS file extension

3D Studio Scene

3D Image Files