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

DOCX file extension

Microsoft Word Open XML Document

Text Files

GBR file extension

Gerber File

Data Files

JSP file extension

Java Server Page

Web Files

KEY file extension

Keynote Presentation

Data Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

TGA file extension

Targa Graphic

Raster Image Files

TIF file extension

Tagged Image File

Raster Image Files

VB file extension

VBScript File

Executable Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

ZIP file extension

Zipped File

Compressed Files

ZIPX file extension

Extended Zip File

Compressed Files

3DS file extension

3D Studio Scene

3D Image Files