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

BIN file extension

Binary Disc Image

Disk Image Files

TIF file extension

Tagged Image File

Raster Image Files

MOBI file extension

Mobipocket eBook

eBook Files

7Z file extension

7-Zip Compressed File

Compressed Files

VCD file extension

Virtual CD

Disk Image Files

SRT file extension

SubRip Subtitle File

Video Files

JAVA file extension

Java Source Code File

Developer Files

CSV file extension

Comma Separated Values File

Data Files

SAV file extension

Saved Game

Game Files

ASF file extension

Advanced Systems Format File

Video Files

CUR file extension

Windows Cursor

System Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

WAV file extension

WAVE Audio File

Audio Files

KEY file extension

Keynote Presentation

Data Files

DEB file extension

Debian Software Package

Compressed Files