ODF and proprietary formats: a comparison

When we create or share a document – whether a simple text, complex spreadsheet or professional presentation – we make a choice that goes far beyond the file extension. This is because the format gives us, or takes away, control over the content.

This post compares the Open Document Format (ODF) with proprietary formats such as DOCX, XLSX and PPTX. The comparison is not just about compatibility, but also about freedom, security, costs, transparency, and our long-term digital future.

We have already discussed ODF, and we will continue to do so until its 10th anniversary as an ISO/IEC standard in May 2026, because it is the only open standard available to users. We hope that an increasing number of users will understand how important it is for them to use it to have complete and lasting control over the content they have created, i.e. for their digital freedom, rather than for those of us who support it.
ODF is the native format of LibreOffice and other programmes that use the LibreOffice Technology platform. These programmes offer the same functionality, flexibility, security, robustness and interoperability as applications that promote proprietary formats, but without the lock-in strategy.

Incidentally, even so-called open-source applications (read their AGPL licence to understand why we say “so-called”) handle documents in ODF format, yet continue to promote their own formats, preventing users from having full control over their content – because this would jeopardise their business strategy.

So, what are proprietary formats?

They are developed and controlled by a single company and are typically only fully supported within that company’s ecosystem. Common examples include .docx, .xlsx and .pptx (Microsoft), as well as .pages, .numbers and .key (Apple) and .gdoc, .gsheet and .gslides (Google). While the specifications for these formats may be public, this does not mean they are completely open, as support is always limited by what the provider allows or documents, and is dictated by their commercial strategies.

Comparison between ODF and proprietary formats

1. Control and vendor lock-in

ODF

• Completely open and standardised
• Anyone can implement or use it without legal restrictions
• The user, not the software provider, controls the documents

Proprietary formats

• Designed and controlled by a single provider
• File characteristics and behaviour may change without notice
• Users are often forced to update their software in order to access their documents

Example: If Microsoft changes how DOCX handles embedded fonts or custom styles, users of older versions of Microsoft software or compatible applications may have difficulty viewing or reading files.

2. Interoperability and compatibility

ODF

• Designed with interoperability in mind
• Promotes consistency in formatting and behaviour across different platforms and software
• Facilitates the development of a multi-vendor ecosystem

Proprietary formats

• Optimised for performance within the vendor’s software
• Third-party implementations often encounter compatibility issues
• File rendering may vary depending on the platform, particularly for advanced formatting

Example: A spreadsheet with complex macros in .xlsx format that works correctly with Excel may not work, or may lose functionality, when used with LibreOffice Calc or Google Sheets.

3. Transparency and trust

ODF

• The format is documented, and matches the documentation
• Data storage is also documented, and users control their files’ location
• There are no secrets or hidden metadata, and the XML file is user readable

Proprietary formats

• They may contain undocumented metadata or behaviour, and the XML file is not user readable
• The complex and opaque structure of the files can create security issues, and files’ location is not controlled by the user
• It is not always clear what information is embedded (e.g. edit history and comments)

Example: a DOCX file may contain residual metadata, such as the names of authors, the date and time of changes, and comments, even after they have been removed.

4. Digital preservation and long-term access

ODF

• Designed for compatibility, interoperability, and long-term archiving
• Recommended by governments (UK, Taiwan, the Netherlands and France) and supranational organisations (EU, NATO)
• Open and future-proof, with regular updates from a known Technical Committee overseen by OASIS

Proprietary formats

• Risk of format obsolescence (remember .doc, .wps and .wpd?)
• Require specific software versions to access older files

Example: a government archive using ODF can be confident that it will still be able to access documents in 20 years’ time, while this is not guaranteed by proprietary formats, which are closely linked to the lifecycles of corporate products.

5. Public sector and legal obligations

Governments and institutions around the world should switch to open standards to ensure data sovereignty and reduce dependence on specific suppliers.

• The UK, Germany, the Netherlands and Taiwan have all launched initiatives to promote ODF
• The European Union’s open-source strategy recommends using ODF in all public administrations
• Italy’s Digital Administration Code supports open formats for public documents to ensure long-term accessibility

Why? Because public data should be open and accessible, not locked behind corporate paywalls or licence terms.

6. Costs and licences

ODF

• Free to use and implement
• No licence fees, subscription costs or vendor lock-in

Proprietary formats

• Almost always tied to paid software (e.g. Microsoft 365)
• In some cases, access requires a cloud account and/or an active subscription
• There are often restrictions on redistribution and format conversion

Example: If a school switches from Microsoft Office to LibreOffice and adopts the OpenDocument Format (ODF), it can save thousands of euros in licence costs without sacrificing functionality for students.

7. Innovation and community support

ODF

• Developed transparently by a global community
• Supported by several applications, both open source and proprietary
• Open to improvements by anyone, under the Technical Committee overview

Proprietary formats

• Innovation is centralised and constrained by the company roadmap, and development is closed and not transparent
• Feature priorities are determined by revenue, and not by user needs

Example: Users can propose new features for ODF, contribute code, and fund development, all without having to wait for the company’s priorities to align with their own.

Conclusion: Why ODF matters

The choice of ODF is not linked to ideology or politics. It is a choice that offers users significant practical benefits: complete control over their data; independence from a single company’s tools, strategies and business model; the ability to access and share documents more reliably on any hardware platform or operating system; and support for an ecosystem where open standards drive progress rather than profit margins. ODF stands for transparency, freedom, and openness to the future. Try it, it’s easy and doesn’t cost anything. Download LibreOffice and you’re done.