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

7Z file extension

7-Zip Compressed File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

INI file extension

Windows Initialization File

Settings Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

SH file extension

Bash Shell Script

Developer Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PNG file extension

Portable Network Graphic

Raster Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files

ZIPX file extension

Extended Zip File

Compressed Files

GBR file extension

Gerber File

Data Files

MAX file extension

3ds Max Scene File

3D Image Files

LOG file extension

Log File

Text Files

HTM file extension

Hypertext Markup Language File

Web Files

RTF file extension

Rich Text Format File

Text Files

PSD file extension

Adobe Photoshop Document

Raster Image Files