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

ASX file extension

Microsoft ASF Redirector File

Video Files

CFM file extension

ColdFusion Markup File

Web Files

CLASS file extension

Java Class File

Developer Files

COM file extension

DOS Command File

Executable Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

IBOOKS file extension

Multi-Touch iBook

Data Files

JPG file extension

JPEG Image

Raster Image Files

LUA file extension

Lua Source File

Developer Files

MAX file extension

3ds Max Scene File

3D Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

UUE file extension

Uuencoded File

Encoded Files

WAV file extension

WAVE Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

ZIP file extension

Zipped File

Compressed Files