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

CBR file extension

Comic Book RAR Archive

Compressed Files

CLASS file extension

Java Class File

Developer Files

DEM file extension

Video Game Demo File

Game Files

JPG file extension

JPEG Image

Raster Image Files

LOG file extension

Log File

Text Files

MAX file extension

3ds Max Scene File

3D Image Files

MDF file extension

Media Disc Image File

Disk Image Files

MSG file extension

Outlook Mail Message

Text Files

NES file extension

Nintendo (NES) ROM File

Game Files

PIF file extension

Program Information File

Executable Files

RPM file extension

Red Hat Package Manager File

Compressed Files

TIF file extension

Tagged Image File

Raster Image Files

TTF file extension

TrueType Font

Font Files

UUE file extension

Uuencoded File

Encoded Files