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

ACCDB file extension

Access 2007 Database File

Database Files

AIF file extension

Audio Interchange File Format

Audio Files

ASX file extension

Microsoft ASF Redirector File

Video Files

EPUB file extension

Open eBook File

eBook Files

JAVA file extension

Java Source Code File

Developer Files

KEY file extension

Keynote Presentation

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

M file extension

Objective-C Implementation File

Developer Files

MDF file extension

Media Disc Image File

Disk Image Files

MP4 file extension

MPEG-4 Video File

Video Files

SQL file extension

Structured Query Language Data File

Database Files

TORRENT file extension

BitTorrent File

Misc Files

VCD file extension

Virtual CD

Disk Image Files

WAV file extension

WAVE Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files