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

AI file extension

Adobe Illustrator File

Vector Image Files

ASP file extension

Active Server Page

Web Files

CBR file extension

Comic Book RAR Archive

Compressed Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

FLA file extension

Adobe Flash Animation

Developer Files

H file extension

C/C++/Objective-C Header File

Developer Files

JS file extension

JavaScript File

Web Files

M4V file extension

iTunes Video File

Video Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PDF file extension

Portable Document Format File

Layout Files

SRT file extension

SubRip Subtitle File

Video Files

VCF file extension

vCard File

Data Files

WAV file extension

WAVE Audio File

Audio Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

XML file extension

XML File

Data Files