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

AZW file extension

Amazon Kindle eBook File

eBook Files

BAT file extension

DOS Batch File

Executable Files

CSR file extension

Certificate Signing Request File

Web Files

FLA file extension

Adobe Flash Animation

Developer Files

FNT file extension

Windows Font File

Font Files

GZ file extension

Gnu Zipped Archive

Compressed Files

JSP file extension

Java Server Page

Web Files

M3U file extension

Media Playlist File

Audio Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PART file extension

Partially Downloaded File

Misc Files

PDB file extension

Program Database

Database Files

PDF file extension

Portable Document Format File

Layout Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RTF file extension

Rich Text Format File

Text Files

TMP file extension

Temporary File

Backup Files