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

AI file extension

Adobe Illustrator File

Vector Image Files

ASX file extension

Microsoft ASF Redirector File

Video Files

CSV file extension

Comma Separated Values File

Data Files

DMP file extension

Windows Memory Dump

System Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

DTD file extension

Document Type Definition File

Developer Files

DXF file extension

Drawing Exchange Format File

CAD Files

LNK file extension

Windows File Shortcut

System Files

MSG file extension

Outlook Mail Message

Text Files

PPS file extension

PowerPoint Slide Show

Data Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

TEX file extension

LaTeX Source Document

Text Files

THM file extension

Thumbnail Image File

Raster Image Files

TTF file extension

TrueType Font

Font Files

WMA file extension

Windows Media Audio File

Audio Files