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

ASP file extension

Active Server Page

Web Files

AVI file extension

Audio Video Interleave File

Video Files

BIN file extension

Binary Disc Image

Disk Image Files

BMP file extension

Bitmap Image File

Raster Image Files

CPL file extension

Windows Control Panel Item

System Files

CSR file extension

Certificate Signing Request File

Web Files

JS file extension

JavaScript File

Web Files

LOG file extension

Log File

Text Files

MPG file extension

MPEG Video File

Video Files

PRF file extension

Outlook Profile File

Settings Files

PY file extension

Python Script

Developer Files

TIF file extension

Tagged Image File

Raster Image Files

WAV file extension

WAVE Audio File

Audio Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

ZIP file extension

Zipped File

Compressed Files