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

TIF file extension

Tagged Image File

Raster Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

M4V file extension

iTunes Video File

Video Files

CSS file extension

Cascading Style Sheet

Web Files

MAX file extension

3ds Max Scene File

3D Image Files

OTF file extension

OpenType Font

Font Files

DBF file extension

Database File

Database Files

MP3 file extension

MP3 Audio File

Audio Files

JAR file extension

Java Archive File

Executable Files

ASF file extension

Advanced Systems Format File

Video Files

MP4 file extension

MPEG-4 Video File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

TTF file extension

TrueType Font

Font Files

KMZ file extension

Google Earth Placemark File

GIS Files

FLV file extension

Flash Video File

Video Files