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

TXT file extension

Plain Text File

Text Files

7Z file extension

7-Zip Compressed File

Compressed Files

VCF file extension

vCard File

Data Files

YUV file extension

YUV Encoded Image File

Raster Image Files

M4V file extension

iTunes Video File

Video Files

AZW file extension

Amazon Kindle eBook File

eBook Files

VOB file extension

DVD Video Object File

Video Files

MOBI file extension

Mobipocket eBook

eBook Files

M3U file extension

Media Playlist File

Audio Files

AIF file extension

Audio Interchange File Format

Audio Files

CGI file extension

Common Gateway Interface Script

Executable Files

LNK file extension

Windows File Shortcut

System Files

M4A file extension

MPEG-4 Audio File

Audio Files

CUR file extension

Windows Cursor

System Files

BIN file extension

Binary Disc Image

Disk Image Files