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

M4V file extension

iTunes Video File

Video Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

RM file extension

Real Media File

Video Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

DRV file extension

Device Driver

System Files

GZ file extension

Gnu Zipped Archive

Compressed Files

KMZ file extension

Google Earth Placemark File

GIS Files

PPS file extension

PowerPoint Slide Show

Data Files

PPT file extension

PowerPoint Presentation

Data Files

ASPX file extension

Active Server Page Extended File

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

KML file extension

Keyhole Markup Language File

GIS Files

TIF file extension

Tagged Image File

Raster Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files