Starting with the 2007 Microsoft Office system, Microsoft Office uses the XML-based file formats, such as .docx, .xlsx, and .pptx. These formats and file name extensions apply to Microsoft Word, Microsoft Excel, and Microsoft PowerPoint. This article discusses key benefits of the format, describes the file name extensions and discusses how you can share Office files with people who are using earlier versions of Office.
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The Open XML Formats include many benefits — not only for developers and the solutions that they build, but also for individual people and organizations of all sizes:
Before you decide to save the file in a binary format, read Can different versions of Office share the same files?
With the file open in your Office app, click File > Save as (or Save a copy, if the file is stored on OneDrive or SharePoint) and make sure the Save as type is set to the modern format.
This will create a new copy of your file, in the Open XML format.
By default, documents, worksheets, and presentations that you create in Office are saved in XML format with file name extensions that add an 'x' or an 'm' to the file name extensions that you are already familiar with. The 'x' signifies an XML file that has no macros, and the 'm' signifies an XML file that does contain macros. For example, when you save a document in Word, the file now uses the .docx file name extension by default, instead of the .doc file name extension.
When you save a file as a template, you see the same kind of change. The template extension used in earlier versions is there, but it now has an 'x' or an 'm' on the end. If the file contains code or macros, you must save it by using the new macro-enabled XML file format, which adds an 'm' for macro to the file extension.
The following tables list all the default file name extensions in Word, Excel, and PowerPoint.
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 |
Office lets you save files in the Open XML Formats and in the binary file format of earlier versions of Office and includes compatibility checkers and file converters to allow file-sharing between different versions of Office.
Opening existing files in Office You can open and work on a file that was created in an earlier version of Office, and then save it in its existing format. Because you might be working on a document with someone who uses an earlier version of Office, Office uses a compatibility checker that verifies that you have not introduced a feature that an earlier version of Office does not support. When you save the file, the compatibility checker reports those features to you and then lets you remove them before continuing with the save.