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

CSR file extension

Certificate Signing Request File

Web Files

DBF file extension

Database File

Database Files

DEM file extension

Video Game Demo File

Game Files

DMP file extension

Windows Memory Dump

System Files

FLV file extension

Flash Video File

Video Files

ICS file extension

iCalendar File

Misc Files

IFF file extension

Interchange File Format

Audio Files

MID file extension

MIDI File

Audio Files

PL file extension

Perl Script

Developer Files

TMP file extension

Temporary File

Backup Files

VOB file extension

DVD Video Object File

Video Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files

3DM file extension

Rhino 3D Model

3D Image Files