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

JPG file extension

JPEG Image

Raster Image Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

JAR file extension

Java Archive File

Executable Files

SAV file extension

Saved Game

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

DAT file extension

Data File

Data Files

BIN file extension

Binary Disc Image

Disk Image Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

GAM file extension

Saved Game File

Game Files

TGA file extension

Targa Graphic

Raster Image Files

DOC file extension

Microsoft Word Document

Text Files

VCD file extension

Virtual CD

Disk Image Files

SYS file extension

Windows System File

System Files

ASF file extension

Advanced Systems Format File

Video Files

CS file extension

Visual C# Source Code File

Developer Files