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

ACCDB file extension

Access 2007 Database File

Database Files

AI file extension

Adobe Illustrator File

Vector Image Files

CAB file extension

Windows Cabinet File

System Files

DDS file extension

DirectDraw Surface

Raster Image Files

DXF file extension

Drawing Exchange Format File

CAD Files

INI file extension

Windows Initialization File

Settings Files

LNK file extension

Windows File Shortcut

System Files

MAX file extension

3ds Max Scene File

3D Image Files

MP3 file extension

MP3 Audio File

Audio Files

TEX file extension

LaTeX Source Document

Text Files

TIF file extension

Tagged Image File

Raster Image Files

VB file extension

VBScript File

Executable Files

WPD file extension

WordPerfect Document

Text Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

ZIPX file extension

Extended Zip File

Compressed Files