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

AVI file extension

Audio Video Interleave File

Video Files

BIN file extension

Binary Disc Image

Disk Image Files

CUE file extension

Cue Sheet File

Disk Image Files

DDS file extension

DirectDraw Surface

Raster Image Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

ICS file extension

iCalendar File

Misc Files

JSP file extension

Java Server Page

Web Files

KMZ file extension

Google Earth Placemark File

GIS Files

LUA file extension

Lua Source File

Developer Files

PAGES file extension

Pages Document

Text Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

PY file extension

Python Script

Developer Files

RTF file extension

Rich Text Format File

Text Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

THM file extension

Thumbnail Image File

Raster Image Files