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

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CSR file extension

Certificate Signing Request File

Web Files

GBR file extension

Gerber File

Data Files

JAVA file extension

Java Source Code File

Developer Files

LOG file extension

Log File

Text Files

M4V file extension

iTunes Video File

Video Files

MSI file extension

Windows Installer Package

Misc Files

PCT file extension

Picture File

Layout Files

PDB file extension

Program Database

Database Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TEX file extension

LaTeX Source Document

Text Files

WSF file extension

Windows Script File

Executable Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

3DM file extension

Rhino 3D Model

3D Image Files