All names on your computer are not created equal. Although you maybe able to choose the name of a file on your computer, but what type of file it is and what particular programs you need to open that file will be determined by the extensions following it.

For example, a file named RossAtTheBeach.jpg with the file extension format “.jpg” tells me computer it is a picture and it needs to open a picture viewing program to see it, when I click on to open that file.

There are many different file extensions your computer uses. Some are industry standards, others are developed by individual people or companies to work with their eco system or software package.

Below is a list and explanation of common file extensions you may have come across on your computer.

Common File Extensions (Formats)

.DOC – Is Microsoft Office’s Word format for making, editing and viewing text documents such as the ones you use in an assignment or for writing a letter.

.TXT – Similar to a .doc file, but pretty much dumbed down. Files with the .txt extensions are plain text files.

.CSV – Are Comma Separated Values files and are usually open with an application like excel which saves data in structured way which is easy to view.

.PPS – Is Microsoft Office’s Powerpoint Presentation format for making presentations.

.MP3 – Compressed Audio files to listen to music, ebooks, audio transcripts etc. Before MP3’s audio files were much larger and less workable.

.AVI – Audio Video Interleave Files are used to watch video and movies etc.

.FLV – Flash video. See those websites which have lots of animation and movies like Youtube.com. They are Flash animations running embedded into those websites but can also be saved and run on your computer also.

.BMP – Bitmap Image File is a image file based on a rectangular grid of pixels to give you a high quality image to view.

.XLS – Microsoft Office’s Excel Spreadsheet software.

.HTML – Basically a webpage. You can save from the internet or create your own webpage. Although not the only web format, the easiest type to save on your computer and open through your web browser.

Other Types of File Formats

Some formats like the ones above you pretty much only see when you need or use and click on them.

But in fact there are a lot of other file formats you use on your computer all the time without even knowing it.

.EXE – Is a Windows Executable file – An executable file is a file which contains a program.  But running a command or double clicking on a executable program you can open it up and start running it, such as clicking on the Itunes icon and start playing music.

.DLL – Dynamic Library Links – Similar to .exe files which contain can contain programming language, data and resources needed for a program to run.