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

CER file extension

Internet Security Certificate

Web Files

EXE file extension

Windows Executable File

Executable Files

IFF file extension

Interchange File Format

Audio Files

MDB file extension

Microsoft Access Database

Database Files

MOV file extension

Apple QuickTime Movie

Video Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPT file extension

PowerPoint Presentation

Data Files

PS file extension

PostScript File

Vector Image Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RM file extension

Real Media File

Video Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

VCXPROJ file extension

Visual C++ Project

Developer Files

VOB file extension

DVD Video Object File

Video Files