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

DB file extension

Database File

Database Files

EPUB file extension

Open eBook File

eBook Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

H file extension

C/C++/Objective-C Header File

Developer Files

HTM file extension

Hypertext Markup Language File

Web Files

JSP file extension

Java Server Page

Web Files

MDB file extension

Microsoft Access Database

Database Files

MDF file extension

Media Disc Image File

Disk Image Files

MOBI file extension

Mobipocket eBook

eBook Files

PY file extension

Python Script

Developer Files

RTF file extension

Rich Text Format File

Text Files

SLN file extension

Visual Studio Solution File

Developer Files

TGA file extension

Targa Graphic

Raster Image Files

TTF file extension

TrueType Font

Font Files

XLR file extension

Works Spreadsheet

Spreadsheet Files