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

ASF file extension

Advanced Systems Format File

Video Files

AVI file extension

Audio Video Interleave File

Video Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CSR file extension

Certificate Signing Request File

Web Files

CSV file extension

Comma Separated Values File

Data Files

FLV file extension

Flash Video File

Video Files

HTM file extension

Hypertext Markup Language File

Web Files

JAR file extension

Java Archive File

Executable Files

PCT file extension

Picture File

Layout Files

PNG file extension

Portable Network Graphic

Raster Image Files

VCF file extension

vCard File

Data Files

VOB file extension

DVD Video Object File

Video Files

WAV file extension

WAVE Audio File

Audio Files

XCODEPROJ file extension

Xcode Project

Developer Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files