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

BIN file extension

Binary Disc Image

Disk Image Files

CLASS file extension

Java Class File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DBF file extension

Database File

Database Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

GED file extension

GEDCOM Genealogy Data File

Data Files

ICO file extension

Icon File

System Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

SWF file extension

Shockwave Flash Movie

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

TARGZ file extension

Compressed Tarball File

Compressed Files

VCXPROJ file extension

Visual C++ Project

Developer Files

WAV file extension

WAVE Audio File

Audio Files

3DS file extension

3D Studio Scene

3D Image Files