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

CAB file extension

Windows Cabinet File

System Files

DAT file extension

Data File

Data Files

DRV file extension

Device Driver

System Files

FLV file extension

Flash Video File

Video Files

FON file extension

Generic Font File

Font Files

M4V file extension

iTunes Video File

Video Files

PAGES file extension

Pages Document

Text Files

SH file extension

Bash Shell Script

Developer Files

SQL file extension

Structured Query Language Data File

Database Files

SRT file extension

SubRip Subtitle File

Video Files

WMA file extension

Windows Media Audio File

Audio Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files

ZIP file extension

Zipped File

Compressed Files

3GP file extension

3GPP Multimedia File

Video Files