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

APP file extension

Mac OS X Application

Executable Files

CSV file extension

Comma Separated Values File

Data Files

DB file extension

Database File

Database Files

DXF file extension

Drawing Exchange Format File

CAD Files

JAVA file extension

Java Source Code File

Developer Files

JSP file extension

Java Server Page

Web Files

MDB file extension

Microsoft Access Database

Database Files

MPA file extension

MPEG-2 Audio File

Audio Files

MPG file extension

MPEG Video File

Video Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

TARGZ file extension

Compressed Tarball File

Compressed Files

VCF file extension

vCard File

Data Files

VOB file extension

DVD Video Object File

Video Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files