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

APK file extension

Android Package File

Executable Files

BAK file extension

Backup File

Backup Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

FON file extension

Generic Font File

Font Files

GBR file extension

Gerber File

Data Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

M4A file extension

MPEG-4 Audio File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

PIF file extension

Program Information File

Executable Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPT file extension

PowerPoint Presentation

Data Files

WAV file extension

WAVE Audio File

Audio Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files