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

TGA file extension

Targa Graphic

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

H file extension

C/C++/Objective-C Header File

Developer Files

RM file extension

Real Media File

Video Files

CER file extension

Internet Security Certificate

Web Files

ASPX file extension

Active Server Page Extended File

Web Files

PART file extension

Partially Downloaded File

Misc Files

SH file extension

Bash Shell Script

Developer Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

AVI file extension

Audio Video Interleave File

Video Files

PDF file extension

Portable Document Format File

Layout Files

ASX file extension

Microsoft ASF Redirector File

Video Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

CUE file extension

Cue Sheet File

Disk Image Files

KML file extension

Keyhole Markup Language File

GIS Files