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

BIN file extension

Binary Disc Image

Disk Image Files

CBR file extension

Comic Book RAR Archive

Compressed Files

DMP file extension

Windows Memory Dump

System Files

DRV file extension

Device Driver

System Files

DTD file extension

Document Type Definition File

Developer Files

JAR file extension

Java Archive File

Executable Files

JS file extension

JavaScript File

Web Files

LOG file extension

Log File

Text Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PHP file extension

PHP Source Code File

Web Files

PL file extension

Perl Script

Developer Files

RM file extension

Real Media File

Video Files

TXT file extension

Plain Text File

Text Files

VOB file extension

DVD Video Object File

Video Files

YUV file extension

YUV Encoded Image File

Raster Image Files