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

AIF file extension

Audio Interchange File Format
Audio Files

CLASS file extension

Java Class File
Developer Files

DAT file extension

Data File
Data Files

IFF file extension

Interchange File Format
Audio Files

KMZ file extension

Google Earth Placemark File
GIS Files

M4A file extension

MPEG-4 Audio File
Audio Files

MAX file extension

3ds Max Scene File
3D Image Files

MIM file extension

Multi-Purpose Internet Mail Message File
Encoded Files

MPA file extension

MPEG-2 Audio File
Audio Files

PDB file extension

Program Database
Database Files

SQL file extension

Structured Query Language Data File
Database Files

SVG file extension

Scalable Vector Graphics File
Vector Image Files

VB file extension

VBScript File
Executable Files

WMA file extension

Windows Media Audio File
Audio Files

YUV file extension

YUV Encoded Image File
Raster Image Files