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

AIF file extension

Audio Interchange File Format

Audio 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

BIN file extension

Binary Disc Image

Disk Image Files

CUR file extension

Windows Cursor

System Files

INI file extension

Windows Initialization File

Settings Files

LOG file extension

Log File

Text Files

MAX file extension

3ds Max Scene File

3D Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PART file extension

Partially Downloaded File

Misc Files

PCT file extension

Picture File

Layout Files

ROM file extension

N64 Game ROM File

Game Files

VCXPROJ file extension

Visual C++ Project

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files