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

APK file extension

Android Package File

Executable Files

CSR file extension

Certificate Signing Request File

Web Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

EPUB file extension

Open eBook File

eBook Files

ICS file extension

iCalendar File

Misc Files

PAGES file extension

Pages Document

Text Files

RM file extension

Real Media File

Video Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TMP file extension

Temporary File

Backup Files

UUE file extension

Uuencoded File

Encoded Files

VCF file extension

vCard File

Data Files

WPD file extension

WordPerfect Document

Text Files

ZIP file extension

Zipped File

Compressed Files

ZIPX file extension

Extended Zip File

Compressed Files