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

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

CSR file extension

Certificate Signing Request File

Web Files

DDS file extension

DirectDraw Surface

Raster Image Files

AIF file extension

Audio Interchange File Format

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

WSF file extension

Windows Script File

Executable Files

GADGET file extension

Windows Gadget

Executable Files

MAX file extension

3ds Max Scene File

3D Image Files

PHP file extension

PHP Source Code File

Web Files

HTM file extension

Hypertext Markup Language File

Web Files

PL file extension

Perl Script

Developer Files

APK file extension

Android Package File

Executable Files

TIFF file extension

Tagged Image File Format

Raster Image Files

EPUB file extension

Open eBook File

eBook Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files