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

AIF file extension

Audio Interchange File Format

Audio Files

BIN file extension

Binary Disc Image

Disk Image Files

CFG file extension

Configuration File

Settings Files

CSR file extension

Certificate Signing Request File

Web Files

CUR file extension

Windows Cursor

System Files

DB file extension

Database File

Database Files

FLV file extension

Flash Video File

Video Files

FON file extension

Generic Font File

Font Files

GPX file extension

GPS Exchange File

GIS Files

MAX file extension

3ds Max Scene File

3D Image Files

MOBI file extension

Mobipocket eBook

eBook Files

MSG file extension

Outlook Mail Message

Text Files

PPT file extension

PowerPoint Presentation

Data Files

SLN file extension

Visual Studio Solution File

Developer Files

SYS file extension

Windows System File

System Files