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

CBR file extension

Comic Book RAR Archive

Compressed Files

CPL file extension

Windows Control Panel Item

System Files

CUE file extension

Cue Sheet File

Disk Image Files

FLV file extension

Flash Video File

Video Files

H file extension

C/C++/Objective-C Header File

Developer Files

JSP file extension

Java Server Page

Web Files

KMZ file extension

Google Earth Placemark File

GIS Files

LOG file extension

Log File

Text Files

MDB file extension

Microsoft Access Database

Database Files

PART file extension

Partially Downloaded File

Misc Files

PCT file extension

Picture File

Layout Files

ROM file extension

N64 Game ROM File

Game Files

TTF file extension

TrueType Font

Font Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

3DM file extension

Rhino 3D Model

3D Image Files