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

AI file extension

Adobe Illustrator File

Vector Image Files

APK file extension

Android Package File

Executable Files

BAT file extension

DOS Batch File

Executable Files

CER file extension

Internet Security Certificate

Web Files

CSV file extension

Comma Separated Values File

Data Files

DOC file extension

Microsoft Word Document

Text Files

EPUB file extension

Open eBook File

eBook Files

H file extension

C/C++/Objective-C Header File

Developer Files

JSP file extension

Java Server Page

Web Files

M4V file extension

iTunes Video File

Video Files

PDF file extension

Portable Document Format File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

RSS file extension

Rich Site Summary

Web Files

TGA file extension

Targa Graphic

Raster Image Files

ZIPX file extension

Extended Zip File

Compressed Files