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

ODT file extension

OpenDocument Text Document

Text Files

PART file extension

Partially Downloaded File

Misc Files

PRF file extension

Outlook Profile File

Settings Files

COM file extension

DOS Command File

Executable Files

PS file extension

PostScript File

Vector Image Files

TTF file extension

TrueType Font

Font Files

DDS file extension

DirectDraw Surface

Raster Image Files

ZIP file extension

Zipped File

Compressed Files

INI file extension

Windows Initialization File

Settings Files

MPA file extension

MPEG-2 Audio File

Audio Files

AIF file extension

Audio Interchange File Format

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

WAV file extension

WAVE Audio File

Audio Files

AI file extension

Adobe Illustrator File

Vector Image Files