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

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CUR file extension

Windows Cursor

System Files

DNG file extension

Digital Negative Image File

Camera Raw Files

EXE file extension

Windows Executable File

Executable Files

ICNS file extension

Mac OS X Icon Resource File

System Files

JAVA file extension

Java Source Code File

Developer Files

M4V file extension

iTunes Video File

Video Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PART file extension

Partially Downloaded File

Misc Files

PHP file extension

PHP Source Code File

Web Files

TXT file extension

Plain Text File

Text Files

VOB file extension

DVD Video Object File

Video Files

WMA file extension

Windows Media Audio File

Audio Files

YUV file extension

YUV Encoded Image File

Raster Image Files