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

PCT file extension

Picture File

Layout Files

VCD file extension

Virtual CD

Disk Image Files

VCF file extension

vCard File

Data Files

MSI file extension

Windows Installer Package

Misc Files

PNG file extension

Portable Network Graphic

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

RA file extension

Real Audio File

Audio Files

3DS file extension

3D Studio Scene

3D Image Files

MDB file extension

Microsoft Access Database

Database Files

UUE file extension

Uuencoded File

Encoded Files

DB file extension

Database File

Database Files

RTF file extension

Rich Text Format File

Text Files

ACCDB file extension

Access 2007 Database File

Database Files

TIF file extension

Tagged Image File

Raster Image Files

CLASS file extension

Java Class File

Developer Files