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

ACCDB file extension

Access 2007 Database File

Database Files

APK file extension

Android Package File

Executable Files

ASF file extension

Advanced Systems Format File

Video Files

DB file extension

Database File

Database Files

DNG file extension

Digital Negative Image File

Camera Raw Files

GADGET file extension

Windows Gadget

Executable Files

JPG file extension

JPEG Image

Raster Image Files

KMZ file extension

Google Earth Placemark File

GIS Files

MID file extension

MIDI File

Audio Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PY file extension

Python Script

Developer Files

RA file extension

Real Audio File

Audio Files

SH file extension

Bash Shell Script

Developer Files

SYS file extension

Windows System File

System Files

TTF file extension

TrueType Font

Font Files