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

AZW file extension

Amazon Kindle eBook File

eBook Files

BAT file extension

DOS Batch File

Executable Files

CSV file extension

Comma Separated Values File

Data Files

DEB file extension

Debian Software Package

Compressed Files

ISO file extension

Disc Image File

Disk Image Files

JSP file extension

Java Server Page

Web Files

KMZ file extension

Google Earth Placemark File

GIS Files

MDB file extension

Microsoft Access Database

Database Files

OTF file extension

OpenType Font

Font Files

PCT file extension

Picture File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

SDF file extension

Standard Data File

Data Files

SH file extension

Bash Shell Script

Developer Files

TXT file extension

Plain Text File

Text Files

WMA file extension

Windows Media Audio File

Audio Files