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

DOC file extension

Microsoft Word Document

Text Files

FLV file extension

Flash Video File

Video Files

GBR file extension

Gerber File

Data Files

ICO file extension

Icon File

System Files

JAR file extension

Java Archive File

Executable Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

LNK file extension

Windows File Shortcut

System Files

PDB file extension

Program Database

Database Files

PHP file extension

PHP Source Code File

Web Files

PL file extension

Perl Script

Developer Files

PRF file extension

Outlook Profile File

Settings Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

VCD file extension

Virtual CD

Disk Image Files

ZIP file extension

Zipped File

Compressed Files