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

BMP file extension

Bitmap Image File

Raster Image Files

CFG file extension

Configuration File

Settings Files

CGI file extension

Common Gateway Interface Script

Executable Files

DBF file extension

Database File

Database Files

DOC# file extension

Microsoft Word Document

Text Files

EXE file extension

Windows Executable File

Executable Files

ODT file extension

OpenDocument Text Document

Text Files

PART file extension

Partially Downloaded File

Misc Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TOAST file extension

Toast Disc Image

Disk Image Files

TXT file extension

Plain Text File

Text Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

ZIP file extension

Zipped File

Compressed Files