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

BAK file extension

Backup File

Backup Files

BIN file extension

Binary Disc Image

Disk Image Files

CSV file extension

Comma Separated Values File

Data Files

CUE file extension

Cue Sheet File

Disk Image Files

DAT file extension

Data File

Data Files

DBF file extension

Database File

Database Files

DOC file extension

Microsoft Word Document

Text Files

JPG file extension

JPEG Image

Raster Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MPG file extension

MPEG Video File

Video Files

OTF file extension

OpenType Font

Font Files

SDF file extension

Standard Data File

Data Files

WMA file extension

Windows Media Audio File

Audio Files

ZIP file extension

Zipped File

Compressed Files