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

BAK file extension

Backup File

Backup Files

DAT file extension

Data File

Data Files

DEB file extension

Debian Software Package

Compressed Files

DTD file extension

Document Type Definition File

Developer Files

DXF file extension

Drawing Exchange Format File

CAD Files

JAVA file extension

Java Source Code File

Developer Files

JSP file extension

Java Server Page

Web Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

PL file extension

Perl Script

Developer Files

PY file extension

Python Script

Developer Files

SH file extension

Bash Shell Script

Developer Files

TEX file extension

LaTeX Source Document

Text Files

3GP file extension

3GPP Multimedia File

Video Files