File Extensions

Learning Outcomes

  • Distinguish different file types in Word and when to use them.

Let’s start by taking a look at the following scenario:

Roy is working on a report that needs to be done before noon so his coworker Salomé can present the data to some prospective customers. Roy just barely manages to finish formatting the final draft. Quickly he saves the file in Microsoft Word, emails the file to Salomé, and leaves to have a well-deserved lunch. When he gets back, Salomé tells him she couldn’t open his file, and as a result she didn’t have the data the customers wanted and lost the sale.

Roy tries to figure out what went wrong and learns that Salomé is running a different version of Microsoft Word than he is, but he’s not sure how that caused the problem.

What can cause this kind of problem? Using the wrong file extension.

A file extension is a shortened form of the file type at the end of a file name. These extensions determine your document’s file type, and the file type determines what programs can open the file. While most programs can read most file types, not every program can read every file type.

The default file type is .docx (Word Document). This file extension works in most Microsoft Word programs. However, there may be times when you want to save a different file type. For example, older versions of Microsoft Word and computers without Microsoft Word installed cannot read .docx file types. If you create a .docx file and send it to someone who has an old version of Word or no Word at all, that person probably won’t be able to read your file.

Because of the variation in file type compatibility, it’s important to be mindful of what file types are readable by the programs other people have.

Below the field for the file name is the “Save as type” field, which has a dropdown menu with file extensions. Your selection for the type of file will automatically add the file extension to the end of your file name. For example, in the screenshot below, inputting a file name of Rowan Retail and choosing the default type of Word Document would result in a file that is named Rowan Retail.docx. Note that you do not type in the file extension as part of the file name. As you will see later on, this type of menu and the choice of file type is also used in other computer applications.

A dropdown menu in a "Save As" dialog box from Microsoft Word displaying file format options including Word Document, Word Macro-Enabled Document, Word 97-2003 Document, Word Template, Word Macro-Enabled Template, Word 97-2003 Template, PDF, XPS Document, Single File Web Page, Web Page, Web Page, Filtered, Rich Text Format, Plain Text, Word XML Document, Word 2003 XML Document, Strict Open XML Document, and OpenDocument Text.

Common File Extensions in Word Processing

  • .docx (Word Document)—default Microsoft Word file, works with Microsoft Word 2007 and later. Improved scripts, macros, and other features from the older .doc.
  • .doc (Word 97–2003 Document)—default Microsoft Word file from Microsoft Word 2003 and older.
  • .txt (Plain Text)—also known as plain text format. This file type saves only the words you type—no images, no formatting, just raw text.
  • .rtf (Rich Text Format)—Like plain text, RTF saves only words, but it does save some basic formatting (like bold and italics)
  • .pdf (PDF)—PDF files are readable with Microsoft Edge (which comes with Windows 10), the free program Adobe Acrobat, and other image-viewing programs. Viewers cannot edit PDF files, but they will be able to view them regardless of their operating system or what programs they have.

Practice Question