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

ASP file extension

Active Server Page

Web Files

AZW file extension

Amazon Kindle eBook File

eBook Files

CFG file extension

Configuration File

Settings Files

FLV file extension

Flash Video File

Video Files

FON file extension

Generic Font File

Font Files

JSP file extension

Java Server Page

Web Files

M file extension

Objective-C Implementation File

Developer Files

MPG file extension

MPEG Video File

Video Files

PDB file extension

Program Database

Database Files

PDF file extension

Portable Document Format File

Layout Files

TOAST file extension

Toast Disc Image

Disk Image Files

UUE file extension

Uuencoded File

Encoded Files

WMA file extension

Windows Media Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files