ODT vs DOCX: The Open Document Format Showdown

ODT vs DOCX is one of those format wars most people never realised was happening. They both look like word processor files. They both work in most modern tools. But the choice between them affects portability, longevity, and the politics of who owns your documents — and the right answer depends on the kind of work you do.

What each format actually is

Both are zipped XML packages — open the file with an unzip tool and you'll see a similar internal structure: XML for content, separate XML for styles, embedded images in a media folder.

The difference:

• DOCX is part of Office Open XML (OOXML), standardised as ISO/IEC 29500 in 2008. Microsoft drove the standardisation and remains the primary implementer.
• ODT is part of OpenDocument Format (ODF), standardised as ISO/IEC 26300 in 2006. The OpenDocument Foundation drove standardisation; LibreOffice and OpenOffice are the primary implementers.

Both are ISO standards. Both are open. The difference is mostly which ecosystem you live in.

Compatibility in 2026

A real-world snapshot of who supports what:

• Microsoft Word: opens both, edits both, but slightly prefers DOCX. Saves as DOCX by default.
• LibreOffice Writer: opens both, edits both, slightly prefers ODT. Saves as ODT by default; DOCX export is excellent.
• Google Docs: imports DOCX cleanly, imports ODT with some rough edges, exports either.
• Apple Pages: opens DOCX well, ODT support is rougher.
• WPS Office: built around DOCX, opens ODT.
• OnlyOffice: handles both, optimised for DOCX/XLSX/PPTX.

In practice, both formats work in most tools, but DOCX is more likely to round-trip cleanly through unfamiliar software.

When ODT is the right choice

• You want a fully open ecosystem. ODT is the default of LibreOffice; using it signals "I'm not in Microsoft's stack."
• Long-term independence from any single vendor. ODT has no dominant implementer who could change direction. DOCX is closely tied to Microsoft's roadmap.
• Government and public-sector contexts. Many EU governments mandate ODF for internal documents.
• You only collaborate with LibreOffice users. ODT is LibreOffice's native format; round-trips are perfect.
• Archival storage for editable documents. ODF is favoured by some national archives over OOXML.

When DOCX is the right choice

• You collaborate with Microsoft Word users. Almost guaranteed compatibility.
• You exchange documents with the wider business world. DOCX is the de facto standard.
• You work with form fields, tracked changes, comments. DOCX support is more mature in most tools.
• You convert frequently to PDF. Word's PDF export is excellent; LibreOffice's is also good but not always identical.
• You use mainstream document automation tools. Most expect DOCX input.

Round-trip quality

The honest measure of compatibility is "can I save in one format, open in a different tool, and get the same result?"

• DOCX → Word → ODT → LibreOffice → DOCX: usually fine for plain documents. Complex tables and SmartArt-like graphics may shift.
• ODT → LibreOffice → DOCX → Word → ODT: similar, with slightly more risk of style changes.
• Round-tripping forms: imperfect in either direction. Word and LibreOffice implement form controls differently.
• Round-tripping tracked changes: usually works but timestamps and authors may shift.
• Round-tripping macros: don't expect this to work. Microsoft VBA macros and LibreOffice Basic are different platforms.

For documents that bounce between Word and LibreOffice users, stick with DOCX — it has the most predictable behaviour in both.

File size

For typical text documents, ODT and DOCX are similar in size, both compressed. Differences:

• DOCX often has slightly more boilerplate XML.
• ODT's metadata is generally more compact.
• For documents with many embedded images, the format choice barely matters — the images dominate file size.

In practice, file size isn't a meaningful differentiator.

Form fields

Both formats support forms, but with different features:

• ODT: form controls via the LibreOffice form designer. Functional but less polished UI.
• DOCX: native Microsoft form controls plus content controls (a newer, more flexible system).

For interactive forms, DOCX is generally better — but for forms users will fill, you usually want a PDF form anyway.

Macros and scripting

A real divergence:

• DOCX supports VBA macros. Documents with macros are usually saved as .docm to make this explicit.
• ODT supports LibreOffice Basic macros, plus Python and JavaScript scripting via UNO.

Macros are a security concern in both formats. Many email systems block documents with macros by default. For shareable documents, avoid both.

Metadata

Both formats include metadata:

• DOCX: docProps/core.xml and app.xml. See DOCX format explained for what's in there.
• ODT: meta.xml. Roughly the same fields.

Both can leak author info, company name, edit history. Strip before external delivery.

Real-world recommendations

• For everyday office work: DOCX. The compatibility advantage is decisive.
• For LibreOffice-only workflows: ODT. Native is smoother than translated.
• For government documents in jurisdictions that mandate ODF: ODT.
• For archival: PDF/A, regardless. See PDF/A explained.
• For final deliverables: PDF. Both formats are working formats, not delivery formats.
• For collaboration with Google Docs users: either format works; their tool will translate.

What to do with existing files

• If you have legacy .doc files (binary Word format), convert to DOCX. The binary format is fragile. The conversion is one click.
• If you have a mix of DOCX and ODT, pick one as your standard for new work. Don't convert existing files unless you have to — the conversion may shift layout subtly.
• If you collaborate widely, default to DOCX for outgoing files. Save in your preferred format internally.

The political dimension

The ODT/DOCX question has a real political angle:

• DOCX comes from Microsoft, the dominant office software vendor. Critics argue Microsoft's standardisation process for OOXML was rushed and the spec has implementation quirks favouring Microsoft's products.
• ODF is more genuinely community-driven. Critics argue ODF's reach is limited because Microsoft never implemented it as a first-class option.

Both arguments have merit. Most users don't need to engage with this debate; the practical answer for them is "use what your collaborators use."

Conclusion

DOCX and ODT are technically similar, ecosystem-different. Use DOCX for broad compatibility, ODT for LibreOffice-native or politically open contexts. Convert to PDF for final delivery in either case. Docento.app handles DOCX and ODT to PDF conversion in the browser without uploads. For more on the surrounding format landscape, see DOCX format explained and PDF vs Word.