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

HTML file extension

Hypertext Markup Language File

Web Files

AIF file extension

Audio Interchange File Format

Audio Files

SQL file extension

Structured Query Language Data File

Database Files

ASP file extension

Active Server Page

Web Files

APP file extension

Mac OS X Application

Executable Files

7Z file extension

7-Zip Compressed File

Compressed Files

WAV file extension

WAVE Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files

LOG file extension

Log File

Text Files

CPP file extension

C++ Source Code File

Developer Files

M4V file extension

iTunes Video File

Video Files

MSG file extension

Outlook Mail Message

Text Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

BMP file extension

Bitmap Image File

Raster Image Files