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

CUE file extension

Cue Sheet File

Disk Image Files

GBR file extension

Gerber File

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

JPG file extension

JPEG Image

Raster Image Files

KML file extension

Keyhole Markup Language File

GIS Files

MDB file extension

Microsoft Access Database

Database Files

PDF file extension

Portable Document Format File

Layout Files

PIF file extension

Program Information File

Executable Files

RA file extension

Real Audio File

Audio Files

TAR file extension

Consolidated Unix File Archive

Data Files

TGA file extension

Targa Graphic

Raster Image Files

TTF file extension

TrueType Font

Font Files

WAV file extension

WAVE Audio File

Audio Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files