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

BMP file extension

Bitmap Image File

Raster Image Files

COM file extension

DOS Command File

Executable Files

CRX file extension

Chrome Extension

Plugin Files

CSV file extension

Comma Separated Values File

Data Files

DTD file extension

Document Type Definition File

Developer Files

JAVA file extension

Java Source Code File

Developer Files

LOG file extension

Log File

Text Files

MSI file extension

Windows Installer Package

Misc Files

OTF file extension

OpenType Font

Font Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

VCD file extension

Virtual CD

Disk Image Files

VCF file extension

vCard File

Data Files

XCODEPROJ file extension

Xcode Project

Developer Files

3DS file extension

3D Studio Scene

3D Image Files