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

ACCDB file extension

Access 2007 Database File

Database Files

AZW file extension

Amazon Kindle eBook File

eBook Files

CRX file extension

Chrome Extension

Plugin Files

DDS file extension

DirectDraw Surface

Raster Image Files

DNG file extension

Digital Negative Image File

Camera Raw Files

EPUB file extension

Open eBook File

eBook Files

IBOOKS file extension

Multi-Touch iBook

Data Files

JAR file extension

Java Archive File

Executable Files

JSP file extension

Java Server Page

Web Files

MAX file extension

3ds Max Scene File

3D Image Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

ZIP file extension

Zipped File

Compressed Files