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

APK file extension

Android Package File

Executable Files

AZW file extension

Amazon Kindle eBook File

eBook Files

BAK file extension

Backup File

Backup Files

BAT file extension

DOS Batch File

Executable Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

DMP file extension

Windows Memory Dump

System Files

GBR file extension

Gerber File

Data Files

ICO file extension

Icon File

System Files

MP4 file extension

MPEG-4 Video File

Video Files

MPG file extension

MPEG Video File

Video Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

TXT file extension

Plain Text File

Text Files

UUE file extension

Uuencoded File

Encoded Files

WSF file extension

Windows Script File

Executable Files

ZIP file extension

Zipped File

Compressed Files