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

CUR file extension

Windows Cursor

System Files

PART file extension

Partially Downloaded File

Misc Files

H file extension

C/C++/Objective-C Header File

Developer Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

7Z file extension

7-Zip Compressed File

Compressed Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

WAV file extension

WAVE Audio File

Audio Files

RM file extension

Real Media File

Video Files

CPP file extension

C++ Source Code File

Developer Files

SLN file extension

Visual Studio Solution File

Developer Files

DAT file extension

Data File

Data Files

DMP file extension

Windows Memory Dump

System Files

JAVA file extension

Java Source Code File

Developer Files

ASF file extension

Advanced Systems Format File

Video Files

M file extension

Objective-C Implementation File

Developer Files