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

COM file extension

DOS Command File

Executable Files

DBF file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

DRV file extension

Device Driver

System Files

ICS file extension

iCalendar File

Misc Files

JAVA file extension

Java Source Code File

Developer Files

KEY file extension

Keynote Presentation

Data Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PL file extension

Perl Script

Developer Files

RA file extension

Real Audio File

Audio Files

SDF file extension

Standard Data File

Data Files

SITX file extension

StuffIt X Archive

Compressed Files

UUE file extension

Uuencoded File

Encoded Files

ZIP file extension

Zipped File

Compressed Files