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

TORRENT file extension

BitTorrent File

Misc Files

GZ file extension

Gnu Zipped Archive

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

CSS file extension

Cascading Style Sheet

Web Files

XCODEPROJ file extension

Xcode Project

Developer Files

VCF file extension

vCard File

Data Files

ROM file extension

N64 Game ROM File

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

VOB file extension

DVD Video Object File

Video Files

AVI file extension

Audio Video Interleave File

Video Files

PNG file extension

Portable Network Graphic

Raster Image Files

DBF file extension

Database File

Database Files

DAT file extension

Data File

Data Files

MOBI file extension

Mobipocket eBook

eBook Files