ODT to DOCX converts documents saved in OpenDocument Text (.odt) — the ISO/IEC 26300 standardized format used by LibreOffice Writer, Apache OpenOffice, and a number of government agencies, EU institutions, and public-sector systems that require open, vendor-neutral document formats under their procurement or interoperability policies — into Microsoft Word's .docx format. The most common reason someone lands on this tool: they drafted something in LibreOffice Writer, or they received a .odt file from a city council, a ministry, a university department, or an open-source-minded collaborator, and now need to hand it to a colleague or client who only has Microsoft Word, or upload it to a portal that flatly rejects anything other than .docx.
Both formats are, underneath, ZIP archives full of XML — that much is genuinely similar. Open either a .odt or a .docx with an archive tool and you will find the same general shape: a manifest, some metadata, and the document body split across a handful of XML files. Where they diverge is the schema. ODT stores text in content.xml against the OpenDocument schema, with styles defined separately in styles.xml. DOCX stores the same information in document.xml against the Office Open XML schema — standardized separately as ECMA-376 and later ISO/IEC 29500 — with its own styles.xml that shares no structural vocabulary with ODF's. Converting between them means translating one schema's idea of a heading, a list, or a run of bold text into the other's, not simply repackaging the same XML in a different wrapper. That translation step is why headings, body paragraphs, character formatting (bold, italic, underline, font size, color), bulleted and numbered lists, and paragraph alignment carry across reliably, while more structurally specific things — custom paragraph and character styles, header and footer content, footnotes, tracked changes and comments, and embedded OLE objects or drawing shapes — are the parts most likely to need a second look after conversion.
Fonts deserve a specific mention because they cause a specific, predictable kind of confusion. An .odt file typically references a font by name rather than embedding its actual outline data, unless the author explicitly enabled font embedding in LibreOffice, which is an option most people never touch. When the converted .docx is opened on a machine that does not have that exact font installed or licensed, Word silently substitutes a fallback. The text itself is untouched, but line breaks, page breaks, and overall pagination can shift slightly because the substitute font has different character widths. If a converted document opens looking slightly different from how it looked in LibreOffice, that is almost always a font-substitution issue on the receiving machine rather than a flaw in the conversion.
The conversion itself runs entirely in your browser — the .odt file is parsed locally against the ODF namespace and rebuilt as a .docx using the docx JavaScript library, without the file ever being transmitted to a server. That matters for the kind of documents that tend to travel in ODT form: government correspondence, procurement submissions, academic records, and internal reports from organizations with strict data-handling requirements.
Need a fixed, uneditable version to send instead of the .docx? Word to PDF handles that final step.
