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

EPS file extension

Encapsulated PostScript File

Vector Image Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

ICS file extension

iCalendar File

Misc Files

M4A file extension

MPEG-4 Audio File

Audio Files

ZIPX file extension

Extended Zip File

Compressed Files

M file extension

Objective-C Implementation File

Developer Files

SQL file extension

Structured Query Language Data File

Database Files

LUA file extension

Lua Source File

Developer Files

SYS file extension

Windows System File

System Files

UUE file extension

Uuencoded File

Encoded Files

ASP file extension

Active Server Page

Web Files

GPX file extension

GPS Exchange File

GIS Files

7Z file extension

7-Zip Compressed File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

KEY file extension

Keynote Presentation

Data Files