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

BAT file extension

DOS Batch File

Executable Files

DBF file extension

Database File

Database Files

DOC file extension

Microsoft Word Document

Text Files

DOC# file extension

Microsoft Word Document

Text Files

JS file extension

JavaScript File

Web Files

KEY file extension

Keynote Presentation

Data Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

RTF file extension

Rich Text Format File

Text Files

SLN file extension

Visual Studio Solution File

Developer Files

TEX file extension

LaTeX Source Document

Text Files

WMV file extension

Windows Media Video File

Video Files

ZIP file extension

Zipped File

Compressed Files

3DS file extension

3D Studio Scene

3D Image Files

3GP file extension

3GPP Multimedia File

Video Files