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

DB file extension

Database File

Database Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

GED file extension

GEDCOM Genealogy Data File

Data Files

INDD file extension

Adobe InDesign Document

Layout Files

KML file extension

Keyhole Markup Language File

GIS Files

LOG file extension

Log File

Text Files

M file extension

Objective-C Implementation File

Developer Files

MOV file extension

Apple QuickTime Movie

Video Files

PDF file extension

Portable Document Format File

Layout Files

RM file extension

Real Media File

Video Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TEX file extension

LaTeX Source Document

Text Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files