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

COM file extension

DOS Command File

Executable Files

CSS file extension

Cascading Style Sheet

Web Files

ICS file extension

iCalendar File

Misc Files

JPG file extension

JPEG Image

Raster Image Files

JSP file extension

Java Server Page

Web Files

MDF file extension

Media Disc Image File

Disk Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

PY file extension

Python Script

Developer Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

THM file extension

Thumbnail Image File

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files