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

APP file extension

Mac OS X Application

Executable Files

BAT file extension

DOS Batch File

Executable Files

CAB file extension

Windows Cabinet File

System Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CUR file extension

Windows Cursor

System Files

DB file extension

Database File

Database Files

M4V file extension

iTunes Video File

Video Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PCT file extension

Picture File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

VCD file extension

Virtual CD

Disk Image Files

VCF file extension

vCard File

Data Files