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

ASF file extension

Advanced Systems Format File

Video Files

BAT file extension

DOS Batch File

Executable Files

COM file extension

DOS Command File

Executable Files

CSV file extension

Comma Separated Values File

Data Files

DBF file extension

Database File

Database Files

DOC# file extension

Microsoft Word Document

Text Files

FLA file extension

Adobe Flash Animation

Developer Files

ICS file extension

iCalendar File

Misc Files

ISO file extension

Disc Image File

Disk Image Files

JSP file extension

Java Server Page

Web Files

KEY file extension

Keynote Presentation

Data Files

PCT file extension

Picture File

Layout Files

SWF file extension

Shockwave Flash Movie

Video Files

UUE file extension

Uuencoded File

Encoded Files

XCODEPROJ file extension

Xcode Project

Developer Files