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

DXF file extension

Drawing Exchange Format File

CAD Files

3GP file extension

3GPP Multimedia File

Video Files

M file extension

Objective-C Implementation File

Developer Files

PY file extension

Python Script

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

HTM file extension

Hypertext Markup Language File

Web Files

ASP file extension

Active Server Page

Web Files

YUV file extension

YUV Encoded Image File

Raster Image Files

CUE file extension

Cue Sheet File

Disk Image Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

JPG file extension

JPEG Image

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

XML file extension

XML File

Data Files

IBOOKS file extension

Multi-Touch iBook

Data Files

MPG file extension

MPEG Video File

Video Files