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

AZW file extension

Amazon Kindle eBook File

eBook Files

CUR file extension

Windows Cursor

System Files

SDF file extension

Standard Data File

Data Files

RTF file extension

Rich Text Format File

Text Files

7Z file extension

7-Zip Compressed File

Compressed Files

EXE file extension

Windows Executable File

Executable Files

FLA file extension

Adobe Flash Animation

Developer Files

DNG file extension

Digital Negative Image File

Camera Raw Files

DOC file extension

Microsoft Word Document

Text Files

YUV file extension

YUV Encoded Image File

Raster Image Files

AVI file extension

Audio Video Interleave File

Video Files

TGA file extension

Targa Graphic

Raster Image Files

MOBI file extension

Mobipocket eBook

eBook Files

COM file extension

DOS Command File

Executable Files

BMP file extension

Bitmap Image File

Raster Image Files