Office Open XML

Office Open XML (also informally known as OOXML or Microsoft Open XML (MOX))[3] is a zipped, XML-based file format developed by Microsoft for representing spreadsheets, charts, presentations and word processing documents. The format was initially standardized by Ecma (as ECMA-376), and by the ISO and IEC (as ISO/IEC 29500) in later versions.

Microsoft Office 2010 provides read support for ECMA-376, read/write support for ISO/IEC 29500 Transitional, and read support for ISO/IEC 29500 Strict.[4] Microsoft Office 2013 and Microsoft Office 2016 additionally support both reading and writing of ISO/IEC 29500 Strict.[5] While Office 2013 and onward have full read/write support for ISO/IEC 29500 Strict, Microsoft has not yet implemented the strict non-transitional, or original standard, as the default file format yet due to remaining interoperability concerns.[6]


In 2000, Microsoft released an initial version of an XML-based format for Microsoft Excel, which was incorporated in Office XP. In 2002, a new file format for Microsoft Word followed.[7] The Excel and Word formats—known as the Microsoft Office XML formats—were later incorporated into the 2003 release of Microsoft Office.

Microsoft announced in November 2005 that it would co-sponsor standardization of the new version of their XML-based formats through Ecma International as "Office Open XML".[8][9] The presentation was made to Ecma by Microsoft's Jean Paoli and Isabelle Valet-Harper.[10][11]

Standardization process

Microsoft submitted initial material to Ecma International Technical Committee TC45, where it was standardized to become ECMA-376, approved in December 2006.[12]

This standard was then fast-tracked in the Joint Technical Committee 1 of ISO and IEC. After initially failing to pass, an amended version of the format received the necessary votes for approval as an ISO/IEC Standard as the result of a JTC 1 fast-tracking standardization process that concluded in April 2008.[13] The resulting four-part International Standard (designated ISO/IEC 29500:2008) was published in November 2008[14] and can be downloaded from the ITTF.[15] A technically equivalent set of texts is published by Ecma as ECMA-376 Office Open XML File Formats—2nd edition (December 2008); they can be downloaded from their web site.[16]

The ISO standardization of Office Open XML was controversial and embittered,[17] with much discussion both about the specification and about the standardization process.[18] According to InfoWorld:

OOXML was opposed by many on grounds it was unneeded, as software makers could use OpenDocument Format (ODF), a less complicated office software format that was already an international standard.[17]

— InfoWorld

The same InfoWorld article reported that IBM (which supports the ODF format) threatened to leave standards bodies that it said allow dominant corporations like Microsoft to wield undue influence. The article further says that Microsoft was accused of co-opting the standardization process by leaning on countries to ensure that it got enough votes at the ISO for Office Open XML to pass, although it does not specify exactly who accused Microsoft.[17]


Under the Ecma International code of conduct in patent matters,[19] participating and approving member organisations of ECMA are required to make available their patent rights on a reasonable and non-discriminatory (RAND) basis.

Holders of patents which concern ISO/IEC International Standards may agree to a standardized license governing the terms under which such patents may be licensed, in accord with the ISO/IEC/ITU common patent policy.[20]

Microsoft, the main contributor to the standard, provided a covenant not to sue[21] for its patent licensing. The covenant received a mixed reception, with some like the Groklaw blog criticizing it,[22] and others such as Lawrence Rosen, (an attorney and lecturer at Stanford Law School), endorsing it.[23]

Microsoft has added the format to their Open Specification Promise[24] in which

Microsoft irrevocably promises not to assert any Microsoft Necessary Claims against you for making, using, selling, offering for sale, importing or distributing any implementation to the extent it conforms to a Covered Specification […]

This is limited to applications which do not deviate from the ISO/IEC 29500:2008 or Ecma-376 standard and to parties that do not "file, maintain or voluntarily participate in a patent infringement lawsuit against a Microsoft implementation of such Covered Specification".[25][26] The Open Specification Promise was included in documents submitted to ISO/IEC in support of the ECMA-376 fast-track submission.[27] Ecma International asserted that, "The OSP enables both open source and commercial software to implement [the specification]".[28]


The Office Open XML specification exists in a number of versions.

ECMA-376 1st edition (2006)

The ECMA standard is structured in five parts to meet the needs of different audiences.[16]

Part 1. Fundamentals
  • Vocabulary, notational conventions and abbreviations
  • Summary of primary and supporting markup languages
  • Conformance conditions and interoperability guidelines
  • Constraints within the Open Packaging Conventions that apply to each document type
Part 2. Open Packaging Conventions
  • The Open Packaging Conventions (OPC), for the package model and physical package, is defined and used by various document types in various applications from multiple vendors.
  • It defines core properties, thumbnails, digital signatures, and authorizations & encryption capabilities for parts or all of the contents in the package.
  • XML schemas for the OPC are declared as XML Schema Definitions (XSD) and (non-normatively) using RELAX NG (ISO/IEC 19757-2)
Part 3. Primer
  • Informative (non-normative) introduction to WordprocessingML, SpreadsheetML, PresentationML, DrawingML, VML and Shared MLs, providing context and illustrating elements through examples and diagrams
  • Describes the custom XML data-storing facility within a package to support integration with business data
Part 4. Markup Language Reference
  • Contains the reference material for WordprocessingML, SpreadsheetML, PresentationML, DrawingML, Shared MLs and Custom XML Schema, defining every element and attribute including the element hierarchy (parent/child relationships)
  • XML schemas for the markup languages are declared as XSD and (non-normatively) using RELAX NG
  • Defines the custom XML data-storing facility
Part 5. Markup Compatibility and Extensibility
  • Describes extension facilities of OpenXML documents and specifies elements & attributes through which applications can operate across different extensions.

Later versions of the ECMA-376 standard are aligned and technically equivalent to the corresponding ISO standard.

ISO/IEC 29500:2008

The ISO/IEC standard is structured into four parts:[29] Parts 1, 2 and 3 are independent standards; for example, Part 2, specifying Open Packaging Conventions, is used by other file formats including XPS and Design Web Format. Part 4 is to be read as a modification to Part 1, which it requires.

A technically equivalent set of texts is also published by Ecma as ECMA-376 2nd edition (2008).

Part 1. Fundamentals & Markup Language Reference
Consisting of 5560 pages, this part contains:
  • Conformance definitions
  • Reference material for the XML document markup languages defined by the Standard
  • XML schemas for the document markup languages declared using XSD and (non-normatively) RELAX NG
  • Defines the foreign markup facilities
Part 2. Open Packaging Conventions
Consisting of 129 pages, this part contains:
  • A description of the Open Packaging Conventions (package model, physical package)
  • Core properties, thumbnails and digital signatures
  • XML schemas for the OPC are declared using XSD and (non-normatively) RELAX NG
Part 3. Markup Compatibility and Extensibility
Consisting of 40 pages, this part contains:
  • A description of extensions: elements & attributes which define mechanisms allowing applications to specify alternative means of negotiating content
  • Extensibility rules are expressed using NVDL
Part 4. Transitional Migration Features
Consisting of 1464 pages, this part contains:
  • Legacy material such as compatibility settings and the graphics markup language VML
  • A list of syntactic differences between this text and ECMA-376 1st Edition

The standard specifies two levels of document & application conformance, strict and transitional, for each of WordprocessingML, PresentationML and SpreadsheetML, and also specifies applications' descriptions of base and full.

Compatibility between versions

The intent of the changes from ECMA-376 1st Edition to ISO/IEC 29500:2008 was that a valid ECMA-376 document would also be a valid ISO 29500 Transitional document;[30] however, at least one change introduced at the BRM—refusing to allow further values for xsd:boolean—had the effect of breaking backwards-compatibility for most documents.[31] A fix for this had been suggested to ISO/IEC JTC1/SC34/WG4, and was approved in June 2009 as a recommendation for the first revision to Office Open XML.[32]

Applications capable of reading documents compliant to ECMA-376 Edition 1 would regard ISO/IEC 29500-4 Transitional documents containing ISO 8601 dates as corrupt.[33]

Application support

Some older versions of Microsoft Word and Microsoft Office are able to read and write .docx files after installation of the free compatibility pack provided by Microsoft,[34] although some items, such as equations, are converted into images that cannot be edited.[35]

Starting with Microsoft Office 2007, the Office Open XML file formats have become the default file format[36] of Microsoft Office.[37][38] However, due to the changes introduced in the Office Open XML standard, Office 2007 is not wholly in compliance with ISO/IEC 29500:2008.[39] Office 2010 includes support for opening documents of the ISO/IEC 29500:2008-compliant version of Office Open XML, but it can only save documents conforming to the transitional, not the strict, schemas of the specification.[40][41] Note that the intent of the ISO/IEC is to allow the removal of the transitional variant from the ISO/IEC 29500 standard.[41]

The ability to read and write Office Open XML format is, however, not limited to Microsoft Office; other office products are also able to read & write this format:

  • SoftMaker Office 2010 is able to read and write DOCX and XLSX files in its word processor & spreadsheet applications.
  • LibreOffice is able to open and save Office Open XML files.[42]
  • and Apache OpenOffice from version 3.0 has been able to import Office Open XML files, but not save them.[43] Version 3.2 improved this feature with read support even for password-protected Office Open XML files.[44][45][46]
  • The Go-oo fork of OpenOffice could also write OOXML files.
  • KOffice from version 2.2 and later was able to import OOXML files.
  • Calligra Suite is able to import Office Open XML files.
  • NeoOffice, an fork for OS X is able to import, support to save OOXML started in 2017.

Other office products that offer import support for the Office Open XML formats include:

See also


  1. ^ a b c Microsoft. "Register file extensions on third party servers". Retrieved 2009-09-04.
  2. ^ Klaus-Peter Eckert; Jan Henrik Ziesing; Ucheoma Ishionwu. "Document Interoperability: Open Document Format and Office Open XML" (PDF). Fraunhofer Verlag. p. 90.
  3. ^ "The Document Foundation, LibreOffice and OOXML". The Document Foundation. Retrieved 2016-03-22.
  4. ^ Overview of the XML file formats in Office 2010
  5. ^ "XML file name extension reference for Office 2013". Microsoft Technet. Microsoft. Retrieved September 30, 2014.
  6. ^ "XLSX Strict (Office Open XML), ISO 29500-1:2008-2016". Retrieved 2018-09-09.
  7. ^ Brian Jones (2007-01-25). "History of office XML formats (1998–2006)". MSDN blogs.
  8. ^ "Microsoft Co-Sponsors Submission of Office Open XML Document Formats to Ecma International for Standardization". Microsoft. 2005-11-21.
  9. ^ Casson and Ryan, Open Standards, Open Source Adoption in the Public Sector, and Their Relationship to Microsoft’s Market Dominance
  10. ^ Microsoft hands over Office XML specs to Ecma
  11. ^ Slides presented by the TC45 committee to Ecma International
  12. ^ "Ecma International approves Office Open XML standard". Ecma International. 2006-12-07.
  13. ^ "ISO/IEC DIS 29500 receives necessary votes for approval as an International Standard". ISO. 2008-04-02.
  14. ^ ISO/IEC (2008-11-18). "Publication of ISO/IEC 29500:2008, Information technology—Office Open XML formats". ISO. Retrieved 2008-11-19.
  15. ^ "Freely Available Standards". ITTF (ISO/IEC). 2008-11-18.
  16. ^ a b "Standard ECMA-376". Retrieved 2009-05-19.
  17. ^ a b c Kirk, Jeremy (19 November 2008). "ISO publishes Office Open XML specification". InfoWorld. Retrieved 12 June 2010.
  18. ^ "Norwegian standards body implodes over OOXML controversy". Ars Technica.
  19. ^ "Code of Conduct in Patent Matters". Ecma International.
  20. ^ "ISO/IEC/ITU common patent policy".
  21. ^ "Microsoft's Open Specification Promise Eases Web Services Patent Concerns". September 12, 2006. Retrieved 2015-04-18.
  22. ^ "2 Escape Hatches in MS's Covenant Not to Sue". Groklaw. Retrieved 2007-01-29.
  23. ^ Berlind, David (November 28, 2005). "Top open source lawyer blesses new terms on Microsoft's XML file format". ZDNet. Retrieved 2007-01-27.
  24. ^ "Microsoft Open Specification Promise". Microsoft. 2007-02-15. Retrieved 2015-04-18.
  25. ^ ""Ecma formal publications"". Ecma International. Ecma Standards and Technical Reports are made available to all interested persons or organizations, free of charge and licensing restrictions
  26. ^ "Microsoft Open Specification Promise".
  27. ^ "Licensing conditions that Microsoft offers for Office Open XML". 2006-12-20. Archived from the original on April 23, 2008. Retrieved 2009-05-19.
  28. ^ "Microsoft Word — Responses to Comments and Perceived Contradictions.doc" (PDF). Retrieved 2009-09-16.
  29. ^ "ISO search for "29500"". International Organization for Standardization. 2009-06-05.
  30. ^ "Re-introducing on/off-values to ST-OnOff in OOXML Part 4". Retrieved 2009-09-29.
  31. ^ "OOXML and Office 2007 Conformance: a Smoke Test". Retrieved 2009-09-29.
  32. ^ "Minutes of the Copenhagen Meeting of ISO/IEC JTC1/SC34/WG4" (PDF). 2009-06-22. Retrieved 2009-09-29. page 15
  33. ^ "ISO/IEC 29500-4:2008/Draft Amd2:2011 - Draft - Information technology — Document description and processing languages — Office Open XML File Formats — Part 4: Transitional Migration Features - AMENDMENT 2" (PDF). 2011-03-02. Retrieved 2011-04-04
  34. ^ "Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats (Version 3)". Microsoft. 2007-06-18. Retrieved 2018-06-23.
  35. ^ Open a Word 2007 document in an earlier version of Word - Word - Retrieved on 2013-07-17.
  36. ^ "Microsoft Expands List of Formats Supported in Microsoft Office". Microsoft. Retrieved 2008-05-21.
  37. ^ "Microsoft's future lies somewhere beyond the Vista by Evansville Courier & Press". Retrieved 2009-05-19.
  38. ^ "Rivals Set Their Sights on Microsoft Office: Can They Topple the Giant? - Knowledge@Wharton". Retrieved 2009-05-19.
  39. ^ Andy Updegrove. "Microsoft Office 2007 to Support ODF — and not OOXML". Retrieved 2009-05-19.
  40. ^ "ISO OOXML convener: Microsoft's format "heading for failure"". Ars Technica.
  41. ^ a b Brown, Alex (31 March 2010). "Microsoft Fails the Standards Test". Where is an end of it?. Alex Brown's weblog. Retrieved 23 June 2018.
  42. ^ "LibreOffice OOXML". Retrieved 22 March 2012.
  43. ^ " 3.0 New Features". 2008-10-13. Retrieved 2009-10-24.
  44. ^ " 3.2 New Features". 2010. Retrieved 2010-11-13.
  45. ^ Scott Gilbertson (13 February 2010). "OpenOffice 3.2 - now with less Microsoft envy". The Register. Retrieved 18 Feb 2013. the ability to open password-protected Word, Excel, and PowerPoint files
  46. ^ "3.2.0 (build OOO320_m12) - Release Notes". Retrieved 18 Feb 2013. Import of password protected Microsoft Office XML files

Further reading

External links

Apache POI

Apache POI, a project run by the Apache Software Foundation, and previously a sub-project of the Jakarta Project, provides pure Java libraries for reading and writing files in Microsoft Office formats, such as Word, PowerPoint and Excel.

Comparison of Office Open XML and OpenDocument

This is a comparison of the Office Open XML document file format with the OpenDocument file format.

Comparison of Office Open XML software

The Office Open XML format (OOXML), is an open and free document file format for saving and exchanging editable office documents such as text documents (including memos, reports, and books), spreadsheets, charts, and presentations.The following tables list applications supporting a version of the Office Open XML standard (ECMA-376 and ISO/IEC 29500:2008).

Comparison of document markup languages

The following tables compare general and technical information for a number of document markup languages. Please see the individual markup languages' articles for further information.

Document file format

A document file format is a text or binary file format for storing documents on a storage media, especially for use by computers.

There currently exists a multitude of incompatible document file formats.

A rough consensus has been established that XML is to be the technical basis for future document file formats, although PDF is likely to remain the format of choice for fixed-layout documents. Examples of XML-based open standards are DocBook, XHTML, and, more recently, the ISO/IEC standards OpenDocument (ISO 26300:2006) and Office Open XML (ISO 29500:2008).

In 1993, the ITU-T tried to establish a standard for document file formats, known as the Open Document Architecture (ODA) which was supposed to replace all competing document file formats. It is described in ITU-T documents T.411 through T.421, which are equivalent to ISO 8613. It did not succeed.

Page description languages such as PostScript and PDF have become the de facto standard for documents that a typical user should only be able to create and read, not edit. In 2001, a series of ISO/IEC standards for PDF began to be published, including the specification for PDF itself, ISO-32000.

HTML is the most used and open international standard and it is also used as document file format. It has also become ISO/IEC standard (ISO 15445:2000).

The default binary file format used by Microsoft Word (.doc) has become widespread de facto standard for office documents, but it is a proprietary format and is not always fully supported by other word processors.

Ecma International

Ecma is a standards organization for information and communication systems. It acquired its current name in 1994, when the European Computer Manufacturers Association (ECMA) changed its name to reflect the organization's global reach and activities. As a consequence, the name is no longer considered an acronym and no longer uses full capitalization.

The organization was founded in 1961 to standardize computer systems in Europe. Membership is open to large and small companies worldwide that produce, market or develop computer or communication systems, and have interest and experience in the areas addressed by the group's technical bodies. It is located in Geneva.


ISO/IEC JTC 1/SC 34, Document description and processing languages is a subcommittee of the ISO/IEC JTC1 joint technical committee, which is a collaborative effort of both the International Organization for Standardization and the International Electrotechnical Commission, which develops and facilitates standards within the field of document description and processing languages. The international secretariat of ISO/IEC JTC 1/SC 34 is the Japanese Industrial Standards Committee (JISC) located in Japan.

List of Microsoft Office filename extensions

The following is a list of Microsoft Office filename extensions, used in Microsoft Office software suite as of January 2017.

List of document markup languages

The following is a list of document markup languages. You may also find the List of markup languages of interest.

List of software that supports Office Open XML

This is an overview of software support for the Office Open XML format, a Microsoft document file format for saving and exchanging editable office documents.

The list here is not exhaustive.

Microsoft Office 2007

Microsoft Office 2007 (codenamed Office 12) is a version of Microsoft Office, a family of office suites and productivity software for Windows, developed and published by Microsoft. It was released to manufacturing on November 3, 2006; it was subsequently made available to volume license customers on November 30, 2006, and later to retail on January 30, 2007, the same respective release dates of Windows Vista. It was preceded by Office 2003 and succeeded by Office 2010.

Office 2007 introduced a new graphical user interface called the Fluent User Interface, which uses ribbons and an Office menu instead of menu bars and toolbars. Office 2007 also introduced Office Open XML file formats as the default file formats in Excel, PowerPoint, and Word. The new formats are intended to facilitate the sharing of information between programs, improve security, reduce the size of documents, and enable new recovery scenarios.Office 2007 requires Windows XP with Service Pack 2, Windows Server 2003 with Service Pack 1, or a later operating system; it is the last version of Microsoft Office to run on Windows XP Professional x64 Edition.Office 2007 includes new applications and server-side tools, including Microsoft Office Groove, a collaboration and communication suite for smaller businesses, which was originally developed by Groove Networks before being acquired by Microsoft in 2005. Also included is Office SharePoint Server 2007, a major revision to the server platform for Office applications, which supports Excel Services, a client-server architecture for supporting Excel workbooks that are shared in real time between multiple machines, and are also viewable and editable through a web page.

With Microsoft FrontPage discontinued, Microsoft SharePoint Designer, which is aimed towards development of SharePoint portals, becomes part of the Office 2007 family. Its designer-oriented counterpart, Microsoft Expression Web, is targeted for general web development. However, neither application has been included in Office 2007 software suites.

Speech recognition functionality has been removed from the individual programs in the Office 2007 suite, as Windows Speech Recognition was integrated into Windows Vista. Windows XP users must install a previous version of Office to use speech recognition features.According to Forrester Research, as of May 2010, Microsoft Office 2007 is used in 81% of enterprises it surveyed (its sample comprising 115 North American and European enterprise and SMB decision makers).

Microsoft Office XML formats

The Microsoft Office XML formats are XML-based document formats (or XML schemas) introduced in versions of Microsoft Office prior to Office 2007. Microsoft Office XP introduced a new XML format for storing Excel spreadsheets and Office 2003 added an XML-based format for Word documents.

These formats were succeeded by Office Open XML (ECMA-376) in Microsoft Office 2007.

Microsoft Word Viewer

Microsoft Word Viewer is a discontinued freeware program for Microsoft Windows that can display and print Microsoft Word documents. Word Viewer allows text from a Word document to be copied into clipboard and pasted into a word processor. The last version made was compatible with Word 2007.

According to the license terms of the Microsoft Word Viewer, the software may be installed and used only to view and screen print documents created with Microsoft Office software. The software may not be used for any other purpose. Users may distribute the software only with a file created with Microsoft Office software to enable recipient to view and print the file.In November 29, 2017, Microsoft had announced that Word Viewer would be retired on that month, no longer receive security updates nor be available to download, and recommended using Office Online, mobile versions of Word, and Office desktop apps for viewing and printing documents free of charge. Microsoft Office 2003 and newer versions are trialware and can also be used for viewing and printing during or after the trial period.

Office Open XML file formats

The Office Open XML file formats are a set of file formats that can be used to represent electronic office documents. There are formats for word processing documents, spreadsheets and presentations as well as specific formats for material such as mathematical formulae, graphics, bibliographies etc.

The formats were developed by Microsoft and first appeared in Microsoft Office 2007. They were standardized between December 2006 and November 2008, first by the Ecma International consortium, where they became ECMA-376, and subsequently, after a contentious standardization process, by the ISO/IEC's Joint Technical Committee 1, where they became ISO/IEC 29500:2008.

Open Packaging Conventions

The Open Packaging Conventions (OPC) is a container-file technology initially created by Microsoft to store a combination of XML and non-XML files that together form a single entity such as an Open XML Paper Specification (OpenXPS) document. OPC-based file formats combine the advantages of leaving the independent file entities embedded in the document intact and resulting in much smaller files compared to normal use of XML.


SpreadsheetML is the XML schema for Microsoft Office Excel 2003.

The Office 2003 XML Reference Schemas are included in the Microsoft Open Specification Promise, a legal statement concerning unrestricted use of Microsoft intellectual property.

Standardization of Office Open XML

The Office Open XML file formats were standardised between December 2006 and November 2008, first by the Ecma International consortium (where they became ECMA-376), and subsequently, after a contentious standardization process, by the ISO/IEC's Joint Technical Committee 1 (where they became ISO/IEC 29500:2008).

Uniform Office Format

Uniform Office Format (UOF; Chinese 标文通, literally "standard text general"), sometimes known as Unified Office Format, is an open standard for office applications developed in China. It includes word processing, presentation, and spreadsheet modules, and is made up of GUI, API, and format specifications. The document format described uses XML contained in a compressed file container, similar to OpenDocument and Office Open XML.

The working group that produced the standard was founded in January 2002, and the first draft of the specification was produced in December 2005.

Vector Markup Language

Vector Markup Language (VML) was an XML-based file format for two-dimensional vector graphics.

VML was specified in Part 4 of the Office Open XML standards ISO/IEC 29500 and ECMA-376. According to the specification, VML is a deprecated format included in Office Open XML for legacy reasons only.VML was pervasively used in MS Office 2007 documents (i.e. Word, Excel and PowerPoint documents).As of 2012, with the release of Internet Explorer 10, VML became obsolete and is no longer supported by Internet Explorer standard mode. It is a legacy feature that is available in Internet Explorer 10 only when the browser is set to run in modes that emulate the functionality of previous versions of Internet Explorer 6, 7, 8, and 9.

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Standards of Ecma International
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