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

AIF file extension

Audio Interchange File Format

Audio Files

CSS file extension

Cascading Style Sheet

Web Files

DBF file extension

Database File

Database Files

DLL file extension

Dynamic Link Library

System Files

DMP file extension

Windows Memory Dump

System Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

JAVA file extension

Java Source Code File

Developer Files

LNK file extension

Windows File Shortcut

System Files

M3U file extension

Media Playlist File

Audio Files

MAX file extension

3ds Max Scene File

3D Image Files

PDF file extension

Portable Document Format File

Layout Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

TTF file extension

TrueType Font

Font Files

3DS file extension

3D Studio Scene

3D Image Files