File Extensions Simplified


Have you ever wondered what the characters trailing your file names are for? Read on to get a complete explanation of what they do.  Computers make use of different applications to carry out different tasks. These applications generally use different file types and each file type has its own unique extension.

The extensions make the work of assigning each file to the right application easier for the computer. This is to enable the computer to open these files with the right format to avoid data corruption.  The number one purpose of a file extension is to give additional information about the particular file to the computer. The extensions can also be read by other software on the computer to determine files that are compatible with the software.  During the course of using a computer, you might have come across a situation where you are unable to open a particular file.

Sometimes this might happen because the file has been corrupted, either through virus infection or while it's being transferred. Transferring files through bad media like flash or a hard drive can mess up with the file structure, thereby rendering it useless.  At other times though, you might be unable to open a file simply because you do not have the right application to open the file format. Ooopsy!

But how does your computer know if you have the right application to open a file or not you might ask. Most times, when your computer encounters a file, it reads the extension and compares it with the list of applications installed on it and their respective compatible file formats. When you click to open a file, the computer checks your program settings and attempt to open the file with the application you set as the default to open that particular file format. If you have more than one application that can a file format, then things get a bit more interesting.

Normally, the file is opened with the default application, but at the same time you can instruct the computer to open the file with another application you specified for that particular instance.
For example, let's say you have an text file to open on your windows computer system. The default application to open text files on this operating system is the Notepad. So, when you click the file to open up, the computer launches Notepad application and loads the content of the file on Notepad. This is so because the computer has been instructed to open text files with file extension .txt automatically on Notepad.

But what if you want to add formatting to that text file? You can't do that with Notepad, so you need to open the file with another application. Enters Wordpad.  Wordpad is an alternative application to open files with .txt extensions. To open with Wordpad, you right click the file, select 'Open With' it will bring out a list of applications compatible with the file format and select Wordpad from the list to open the file with Wordpad.

Of note is the fact that this procedure only opens the file with Wordpad once, any other instance of opening the file will be done with the default Notepad. Although, you can change the default application and select Wordpad or any other application you are most comfortable with.

In some situations, the computer might not find a suitable application to open a particular file format. Maybe you don't have the application installed or the version you have is outdated. For example, if you get a graphics design file done with CorelDraw X5 and you either don't have the software installed or the one you have is lower than X5. In that situation, you won't be able to open the file.



So what to do? Depending on the file format, you can go online and search for an application that can open that file or go to your local computer store and purchase the necessary application.

Obviously, you will encounter some file types more often than others, especially if you are a general user of the computer. Below are a few common file extensions you might run into, the file time and examples of applications to open them with.


This file extension is for Microsoft word documents. The old version uses the .doc extension while the new version uses the .docx format. You access this file type with Microsoft Word application.


The PDF file extension is also used for documents. Most PDF files are read only, that is, you can only read the contents, you can't edit to add or remove from it. Although, there are some editable PDF files in circulation.

Applications you can use for this file type includes Adobe Reader, Nitro PDF Reader, PDF Reader, etc.


This extension is for executable files. Executable files most times are used to install applications on your computer system.

For security reasons, make sure you only open EXE files you get from trusted sources, else you stand the risk of installing malware and virus that can damage your computer.


These file extensions are all used for image files. The main difference in the extensions is the compression rate of the picture or image being save. PNG file formats tend to give the best quality of pictures.


Tis is the primary extension for internet webpages. Files with this extension are opened by your web browsers such as Google Chrome, Mozilla Firefox and Safari.
If you are building a website, you can also open HTML files with your editing software like Notepad, Notepad ++, Aptana and Adobe Dreamweaver.

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