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

CS file extension

Visual C# Source Code File

Developer Files

DAT file extension

Data File

Data Files

DNG file extension

Digital Negative Image File

Camera Raw Files

DXF file extension

Drawing Exchange Format File

CAD Files

MDB file extension

Microsoft Access Database

Database Files

PNG file extension

Portable Network Graphic

Raster Image Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TEX file extension

LaTeX Source Document

Text Files

THM file extension

Thumbnail Image File

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

VOB file extension

DVD Video Object File

Video Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

3DS file extension

3D Studio Scene

3D Image Files