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

CSS file extension

Cascading Style Sheet

Web Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

DBF file extension

Database File

Database Files

WPD file extension

WordPerfect Document

Text Files

PAGES file extension

Pages Document

Text Files

SH file extension

Bash Shell Script

Developer Files

HTM file extension

Hypertext Markup Language File

Web Files

MAX file extension

3ds Max Scene File

3D Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

PDF file extension

Portable Document Format File

Layout Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

DEB file extension

Debian Software Package

Compressed Files

CSR file extension

Certificate Signing Request File

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

SAV file extension

Saved Game

Game Files