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

ASP file extension

Active Server Page

Web Files

BIN file extension

Binary Disc Image

Disk Image Files

CSR file extension

Certificate Signing Request File

Web Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

FNT file extension

Windows Font File

Font Files

GAM file extension

Saved Game File

Game Files

H file extension

C/C++/Objective-C Header File

Developer Files

HTML file extension

Hypertext Markup Language File

Web Files

IBOOKS file extension

Multi-Touch iBook

Data Files

MPG file extension

MPEG Video File

Video Files

SH file extension

Bash Shell Script

Developer Files

SRT file extension

SubRip Subtitle File

Video Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TIFF file extension

Tagged Image File Format

Raster Image Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files