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

BIN file extension

Binary Disc Image

Disk Image Files

DAT file extension

Data File

Data Files

H file extension

C/C++/Objective-C Header File

Developer Files

INDD file extension

Adobe InDesign Document

Layout Files

KEY file extension

Keynote Presentation

Data Files

MP4 file extension

MPEG-4 Video File

Video Files

MPG file extension

MPEG Video File

Video Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPT file extension

PowerPoint Presentation

Data Files

PY file extension

Python Script

Developer Files

TAR file extension

Consolidated Unix File Archive

Data Files

TGA file extension

Targa Graphic

Raster Image Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files