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

ASPX file extension

Active Server Page Extended File

Web Files

BAT file extension

DOS Batch File

Executable Files

M file extension

Objective-C Implementation File

Developer Files

M4A file extension

MPEG-4 Audio File

Audio Files

NES file extension

Nintendo (NES) ROM File

Game Files

ODT file extension

OpenDocument Text Document

Text Files

PDB file extension

Program Database

Database Files

ROM file extension

N64 Game ROM File

Game Files

SDF file extension

Standard Data File

Data Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

UUE file extension

Uuencoded File

Encoded Files

WAV file extension

WAVE Audio File

Audio Files

WPD file extension

WordPerfect Document

Text Files

XCODEPROJ file extension

Xcode Project

Developer Files

ZIP file extension

Zipped File

Compressed Files