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

7Z file extension

7-Zip Compressed File

Compressed Files

THM file extension

Thumbnail Image File

Raster Image Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

TMP file extension

Temporary File

Backup Files

CAB file extension

Windows Cabinet File

System Files

ACCDB file extension

Access 2007 Database File

Database Files

FON file extension

Generic Font File

Font Files

LNK file extension

Windows File Shortcut

System Files

PPT file extension

PowerPoint Presentation

Data Files

RSS file extension

Rich Site Summary

Web Files

BMP file extension

Bitmap Image File

Raster Image Files

DMP file extension

Windows Memory Dump

System Files

GBR file extension

Gerber File

Data Files

3GP file extension

3GPP Multimedia File

Video Files

TORRENT file extension

BitTorrent File

Misc Files