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

7Z file extension

7-Zip Compressed File

Compressed Files

WPD file extension

WordPerfect Document

Text Files

TARGZ file extension

Compressed Tarball File

Compressed Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files

DXF file extension

Drawing Exchange Format File

CAD Files

APP file extension

Mac OS X Application

Executable Files

MDB file extension

Microsoft Access Database

Database Files

PPT file extension

PowerPoint Presentation

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

CPP file extension

C++ Source Code File

Developer Files

PCT file extension

Picture File

Layout Files

GZ file extension

Gnu Zipped Archive

Compressed Files

TIF file extension

Tagged Image File

Raster Image Files