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

DOC# file extension

Microsoft Word Document

Text Files

NES file extension

Nintendo (NES) ROM File

Game Files

CFG file extension

Configuration File

Settings Files

OTF file extension

OpenType Font

Font Files

7Z file extension

7-Zip Compressed File

Compressed Files

CSR file extension

Certificate Signing Request File

Web Files

ZIP file extension

Zipped File

Compressed Files

CAB file extension

Windows Cabinet File

System Files

SLN file extension

Visual Studio Solution File

Developer Files

VB file extension

VBScript File

Executable Files

SRT file extension

SubRip Subtitle File

Video Files

JAVA file extension

Java Source Code File

Developer Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

MPA file extension

MPEG-2 Audio File

Audio Files

PAGES file extension

Pages Document

Text Files