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

ASX file extension

Microsoft ASF Redirector File

Video Files

AVI file extension

Audio Video Interleave File

Video Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DNG file extension

Digital Negative Image File

Camera Raw Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IBOOKS file extension

Multi-Touch iBook

Data Files

ISO file extension

Disc Image File

Disk Image Files

JAR file extension

Java Archive File

Executable Files

MOV file extension

Apple QuickTime Movie

Video Files

PHP file extension

PHP Source Code File

Web Files

PPS file extension

PowerPoint Slide Show

Data Files

PY file extension

Python Script

Developer Files

TGA file extension

Targa Graphic

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files