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

ACCDB file extension

Access 2007 Database File

Database Files

ASP file extension

Active Server Page

Web Files

CER file extension

Internet Security Certificate

Web Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

JAR file extension

Java Archive File

Executable Files

KMZ file extension

Google Earth Placemark File

GIS Files

MSI file extension

Windows Installer Package

Misc Files

PRF file extension

Outlook Profile File

Settings Files

PY file extension

Python Script

Developer Files

RA file extension

Real Audio File

Audio Files

TEX file extension

LaTeX Source Document

Text Files

TIF file extension

Tagged Image File

Raster Image Files

TMP file extension

Temporary File

Backup Files

TXT file extension

Plain Text File

Text Files

ZIPX file extension

Extended Zip File

Compressed Files