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

BMP file extension

Bitmap Image File

Raster Image Files

CFG file extension

Configuration File

Settings Files

FNT file extension

Windows Font File

Font Files

HTM file extension

Hypertext Markup Language File

Web Files

IFF file extension

Interchange File Format

Audio Files

JAVA file extension

Java Source Code File

Developer Files

JS file extension

JavaScript File

Web Files

MP3 file extension

MP3 Audio File

Audio Files

RA file extension

Real Audio File

Audio Files

RSS file extension

Rich Site Summary

Web Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TIF file extension

Tagged Image File

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WSF file extension

Windows Script File

Executable Files