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

PS file extension

PostScript File

Vector Image Files

DMP file extension

Windows Memory Dump

System Files

VCD file extension

Virtual CD

Disk Image Files

OTF file extension

OpenType Font

Font Files

MDB file extension

Microsoft Access Database

Database Files

AI file extension

Adobe Illustrator File

Vector Image Files

M4A file extension

MPEG-4 Audio File

Audio Files

MOBI file extension

Mobipocket eBook

eBook Files

ICO file extension

Icon File

System Files

CS file extension

Visual C# Source Code File

Developer Files

SAV file extension

Saved Game

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

DB file extension

Database File

Database Files

BIN file extension

Binary Disc Image

Disk Image Files

GED file extension

GEDCOM Genealogy Data File

Data Files