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

EPS file extension

Encapsulated PostScript File

Vector Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

JAVA file extension

Java Source Code File

Developer Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

PS file extension

PostScript File

Vector Image Files

PNG file extension

Portable Network Graphic

Raster Image Files

SDF file extension

Standard Data File

Data Files

TGA file extension

Targa Graphic

Raster Image Files

H file extension

C/C++/Objective-C Header File

Developer Files

PRF file extension

Outlook Profile File

Settings Files

CLASS file extension

Java Class File

Developer Files

PHP file extension

PHP Source Code File

Web Files

GZ file extension

Gnu Zipped Archive

Compressed Files

BAT file extension

DOS Batch File

Executable Files

EXE file extension

Windows Executable File

Executable Files