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

DBF file extension

Database File

Database Files

DOC file extension

Microsoft Word Document

Text Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

GAM file extension

Saved Game File

Game Files

ICS file extension

iCalendar File

Misc Files

INI file extension

Windows Initialization File

Settings Files

MAX file extension

3ds Max Scene File

3D Image Files

MDB file extension

Microsoft Access Database

Database Files

MP3 file extension

MP3 Audio File

Audio Files

OTF file extension

OpenType Font

Font Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

THM file extension

Thumbnail Image File

Raster Image Files

UUE file extension

Uuencoded File

Encoded Files

WPD file extension

WordPerfect Document

Text Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files