What Is the Difference between Doc and Docx Files?

Whenever you use the Microsoft Word application, you either use files with the .doc or the .docx extensions. Microsoft Word is a part of the Microsoft Office suite. Microsoft used .doc as its solo file format up until the launch of MS Word version 2003. When they subsequently launched MS Word version 2007, Microsoft introduced the new file format, DOCX, which is their default file format up to now.

Let us see what the two formats are.

The DOC Format

Microsoft began using the DOC file format in the 1980s when they released their first Word processor for MS-DOS. This was a proprietary document format for Microsoft, and only MS Word supported the format.

Very soon, competing products worked with DOC files, although few other word processors supported the format totally. This went on until 2008, when Microsoft released an updated version of the DOC format which other programs could use with some functional limitations.

The DOCX Format

In the early 2000s, Open Office was the main competitor to Microsoft. Open Office is an open-source and free office suite that had its own word processor using the Open Document Format or .odf .

Because of the competition, Microsoft developed an even broader open standard. This became the DOCX file format, along with its counterparts like XLSX for spreadsheets and PPTX for PowerPoint presentations.

These new standards from Microsoft came with the name Office Open XML. Their base was the XML or Extensible Markup Language, rather than the older and limited binary format. The new standards offered more benefits, such as lower chances of file corruption, better-looking compressed images, and significantly smaller file sizes.

Now let us see the difference between the two formats.

The Major Difference

The DOC file format is a binary format that contains all the related formatting and other data. On the other hand, the DOCX file is actually a zipped file containing all the XML files of the document.

Therefore, you can replace the DOCX file extension with a zip extension. This allows you to use any zip compression software to open the document.

Other Differences

  • The DOC extension is the default for MS Word 2003, whereas the DOCX extension is the default for MS Word 2007 and above.
  • To open a DOCX file in Word 2003, you need to use a compatibility pack, whereas it is possible to open a DOC file easily in any version of Word.
  • DOCX is based on XML, whereas DOC is a binary format.
  • DOCX is an open format, whereas DOC is proprietary.
  • DOCX permits working with new features, whereas DOC does not.


DOCX, being a later development, is a better option compared to DOC. The DOCX format offers a smaller and lighter file that is easier to open, read, and transfer. While the chances of corruption are lower for DOCX files, they are easier to repair if damaged.

However, the DOC format has its advantages too. It allows you to open and work with files that are over ten years old. If you are using any of the outdated word processors, they are more likely to be compatible with the DOC format.

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