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

DMG file extension

Mac OS X Disk Image

Disk Image Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

CUR file extension

Windows Cursor

System Files

DBF file extension

Database File

Database Files

GED file extension

GEDCOM Genealogy Data File

Data Files

CUE file extension

Cue Sheet File

Disk Image Files

ASP file extension

Active Server Page

Web Files

JAR file extension

Java Archive File

Executable Files

ZIPX file extension

Extended Zip File

Compressed Files

HTM file extension

Hypertext Markup Language File

Web Files

ICNS file extension

Mac OS X Icon Resource File

System Files

ISO file extension

Disc Image File

Disk Image Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

EXE file extension

Windows Executable File

Executable Files