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

APK file extension

Android Package File

Executable Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

ISO file extension

Disc Image File

Disk Image Files

GADGET file extension

Windows Gadget

Executable Files

ASX file extension

Microsoft ASF Redirector File

Video Files

KEY file extension

Keynote Presentation

Data Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

UUE file extension

Uuencoded File

Encoded Files

MP4 file extension

MPEG-4 Video File

Video Files

MPG file extension

MPEG Video File

Video Files

TEX file extension

LaTeX Source Document

Text Files

RTF file extension

Rich Text Format File

Text Files

PDB file extension

Program Database

Database Files

7Z file extension

7-Zip Compressed File

Compressed Files

PAGES file extension

Pages Document

Text Files