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

7Z file extension

7-Zip Compressed File

Compressed Files

FLA file extension

Adobe Flash Animation

Developer Files

ZIPX file extension

Extended Zip File

Compressed Files

FNT file extension

Windows Font File

Font Files

DTD file extension

Document Type Definition File

Developer Files

TOAST file extension

Toast Disc Image

Disk Image Files

GADGET file extension

Windows Gadget

Executable Files

PDB file extension

Program Database

Database Files

LNK file extension

Windows File Shortcut

System Files

TIFF file extension

Tagged Image File Format

Raster Image Files

3G2 file extension

3GPP2 Multimedia File

Video Files

ASP file extension

Active Server Page

Web Files

MPG file extension

MPEG Video File

Video Files

M file extension

Objective-C Implementation File

Developer Files