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

CAB file extension

Windows Cabinet File

System Files

CSR file extension

Certificate Signing Request File

Web Files

DB file extension

Database File

Database Files

DBF file extension

Database File

Database Files

ICS file extension

iCalendar File

Misc Files

LUA file extension

Lua Source File

Developer Files

MAX file extension

3ds Max Scene File

3D Image Files

PHP file extension

PHP Source Code File

Web Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

ROM file extension

N64 Game ROM File

Game Files

SLN file extension

Visual Studio Solution File

Developer Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WMA file extension

Windows Media Audio File

Audio Files

XCODEPROJ file extension

Xcode Project

Developer Files

XLR file extension

Works Spreadsheet

Spreadsheet Files