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

ASP file extension

Active Server Page

Web Files

CPP file extension

C++ Source Code File

Developer Files

CSR file extension

Certificate Signing Request File

Web Files

DDS file extension

DirectDraw Surface

Raster Image Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

MDB file extension

Microsoft Access Database

Database Files

MSG file extension

Outlook Mail Message

Text Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

ROM file extension

N64 Game ROM File

Game Files

RTF file extension

Rich Text Format File

Text Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files

XCODEPROJ file extension

Xcode Project

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files