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

ASF file extension

Advanced Systems Format File

Video Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

FNT file extension

Windows Font File

Font Files

GADGET file extension

Windows Gadget

Executable Files

KEY file extension

Keynote Presentation

Data Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MSG file extension

Outlook Mail Message

Text Files

PDB file extension

Program Database

Database Files

PDF file extension

Portable Document Format File

Layout Files

TORRENT file extension

BitTorrent File

Misc Files

TTF file extension

TrueType Font

Font Files

VCD file extension

Virtual CD

Disk Image Files

WPD file extension

WordPerfect Document

Text Files

ZIP file extension

Zipped File

Compressed Files

3G2 file extension

3GPP2 Multimedia File

Video Files