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

AIF file extension

Audio Interchange File Format

Audio Files

GZ file extension

Gnu Zipped Archive

Compressed Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

IBOOKS file extension

Multi-Touch iBook

Data Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

LUA file extension

Lua Source File

Developer Files

MDB file extension

Microsoft Access Database

Database Files

PCT file extension

Picture File

Layout Files

PIF file extension

Program Information File

Executable Files

TIF file extension

Tagged Image File

Raster Image Files

UUE file extension

Uuencoded File

Encoded Files

VB file extension

VBScript File

Executable Files

VCD file extension

Virtual CD

Disk Image Files

VCF file extension

vCard File

Data Files

3GP file extension

3GPP Multimedia File

Video Files