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

C file extension

C/C++ Source Code File

Developer Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

EPUB file extension

Open eBook File

eBook Files

FNT file extension

Windows Font File

Font Files

LOG file extension

Log File

Text Files

MID file extension

MIDI File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

PART file extension

Partially Downloaded File

Misc Files

PNG file extension

Portable Network Graphic

Raster Image Files

PS file extension

PostScript File

Vector Image Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

ROM file extension

N64 Game ROM File

Game Files

WMV file extension

Windows Media Video File

Video Files

3DM file extension

Rhino 3D Model

3D Image Files