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

APP file extension

Mac OS X Application

Executable Files

GZ file extension

Gnu Zipped Archive

Compressed Files

KEY file extension

Keynote Presentation

Data Files

DRV file extension

Device Driver

System Files

BIN file extension

Binary Disc Image

Disk Image Files

JAVA file extension

Java Source Code File

Developer Files

MP4 file extension

MPEG-4 Video File

Video Files

ISO file extension

Disc Image File

Disk Image Files

VCF file extension

vCard File

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files

TIFF file extension

Tagged Image File Format

Raster Image Files

FON file extension

Generic Font File

Font Files

PY file extension

Python Script

Developer Files

CSR file extension

Certificate Signing Request File

Web Files

YUV file extension

YUV Encoded Image File

Raster Image Files