Introduction to New File-Name Extensions

The 2007 Microsoft Office system introduces a new file format based on XML. It is called Open XML Formats and applies to Microsoft Office Word 2007, Microsoft Office Excel 2007, and Microsoft Office PowerPoint 2007. This article describes about how the new file name extensions arrived at, how you can share the 2007 Office release files with people using earlier versions of Office, and you can learn about the benefits.

In order to understand new file extensions you have to understand documents, templates, worksheets, and presentations created in the Microsoft Office Suite that is a 2007 release. The file are saved with x or an m. for example in a word document when you save it, the new file use .docx extension.

The x signifies an XML file with no macros.

The m signifies an XML file that does contain macros.

This can be illustrated in the figure below;

The following tables list the file extensions in Office Word 2007, Office Excel 2007, and Office PowerPoint 2007.


XML file type Extension
Document .docx
Macro-enabled document .docm
Template .dotx
Macro-enabled template .dotm


XML file type Extension
Workbook .xlsx
Macro-enabled workbook .xlsm
Template .xltx
Macro-enabled template .xltm
Non-XML binary workbook .xlsb
Macro-enabled add-in .xlam


XML file type Extension
Presentation .pptx
Macro-enabled presentation .pptm
Template .potx
Macro-enabled template .potm
Macro-enabled add-in .ppam
Show .ppsx
Macro-enabled show .ppsm
Slide .sldx
Macro-enabled slide .sldm
Office theme .thmx

In understanding if the different versions of Office share the same file, it important to establish the fact that the 2007 office suit has with it compatibility checkers and file converters. This is allows for sharing of files between different versions of office, which include the following way;

When opening previous-version files in the 2007 Office release, you open and work on a file that was created in an earlier version of Office, and then save it in its original format. To prevent introduction of features in the 2007 Office release. The 2007 Office release uses a compatibility checker that reports those features to you and then you can remove them before continuing with the save.

Opening the 2007 Office release files in earlier versions of Office, you can open and edit a 2007 Office release file in an earlier version of Word, Excel, or PowerPoint by downloading file converters. On the computer with an earlier version of Office, go to the Download Center and download the Microsoft Office Compatibility Pack for 2007 Office Word, Excel and PowerPoint File Formats.

Your version of Microsoft Office must be updated to one of the service packs in the following list. After you install the service pack for your version of Office, then download the converter.
Microsoft Office 2000 Service Pack 3
Microsoft Office XP Service Pack 3
Microsoft Office 2003 Service Pack 1


The Open XML Formats introduces several benefits — not only for developers and the solutions that they build, but also for individual people and organizations of all sizes:

Compact files. Files are automatically compressed and can be up to 75 percent smaller in some cases. The Open XML Formats uses zip-compression technology to store documents, offering potential cost savings because it reduces the disk space required to store files, and decreases the bandwidth needed to send files via e-mail, over networks, and across the Internet. When you open a file, it is automatically unzipped. When you save a file, it is automatically zipped again. You do not have to install any special zip programs to open and close files in the 2007 Office release.

Improved damaged-file recovery. Files are structured in a modular fashion that keeps different data components in the file separate from each other. This allows files to be opened even if a component in the file (for example, a chart or table) is damaged or corrupt.

Better privacy and more control over personal information     Documents can be shared confidentially, because personally-identifiable and business-sensitive information, such as author names, comments, tracked changes, and file paths can be identified and removed by using Document Inspector.

Better integration and interoperability of business data     Using Open XML Formats as the data interoperability framework for the 2007 Office release set of products means that documents, worksheets, presentations, and forms can be saved in an XML format available for anyone to use and to license, royalty free. Office also supports customer-defined XML schemas that enhance the existing Office document types. This means that customers can unlock information in existing systems and use it in familiar Office programs. Information that is created by Office programs can be used by other business applications. All you need to open and edit an Office file is a zip utility and an XML editor.

Easier detection of documents that contain macros     Files that are saved by using the default x suffix (such as .docx, .xlsx, and .pptx) cannot contain Visual Basic for Applications (VBA) macros and XLM macros. Only files with file-name extension that end in an m (such as .docm, .xlsm, and .pptm) can contain macros.