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

CUR file extension

Windows Cursor

System Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

EXE file extension

Windows Executable File

Executable Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

M file extension

Objective-C Implementation File

Developer Files

PAGES file extension

Pages Document

Text Files

PL file extension

Perl Script

Developer Files

PPT file extension

PowerPoint Presentation

Data Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

SWF file extension

Shockwave Flash Movie

Video Files

TGA file extension

Targa Graphic

Raster Image Files

TIF file extension

Tagged Image File

Raster Image Files

VCD file extension

Virtual CD

Disk Image Files

XLR file extension

Works Spreadsheet

Spreadsheet Files