What is a .odt file?
OpenDocument Text · Document · OASIS · 2005
ODT is the OpenDocument word-processing format, LibreOffice Writer's default and the open, ISO-standardised counterpart to Microsoft's DOCX. Like DOCX it is a zipped bundle of XML, letting any compliant program read and write it without licensing a proprietary spec.
What is a .odt file used for?
ODT is the OpenDocument word-processing format, the open, vendor-neutral counterpart to DOCX. Like DOCX it is a zip archive of XML, but it comes from a different lineage: the OASIS standards body rather than Microsoft.
LibreOffice Writer and Apache OpenOffice save in ODT by default, and it is mandated for government and public-sector documents in a number of countries that require an open, non-proprietary format.
Microsoft Word opens and saves ODT too, though very complex formatting can shift slightly when it round-trips between the two ecosystems, the same kind of friction DOCX has when opened in LibreOffice.
The format is standardised as ISO/IEC 26300 (approved in 2006), which is what lets any compliant application implement it without licensing it from a single vendor.
How to open a .odt file
The .odt format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- LibreOffice Writer
- Word
- Google Docs
macOS
- LibreOffice Writer
- Word
- Pages (import)
Linux
- LibreOffice Writer
- OnlyOffice
Web
- Google Docs (import)
- Office on the web
How to convert a .odt file
You can convert a .odt file to DOCX, PDF, TXT using a conversion tool or the export menu of an app that opens it.
.odt file signature (magic bytes)
Programs recognise a .odt file by the bytes at the start of the file, not by its name. These are the signatures for ODT. For a full breakdown, see the ODT file signature page.
| Hex signature | Offset | Note |
|---|---|---|
| 50 4B 03 04 | 0 | ZIP/OPC package; a 'mimetype' entry (stored, not compressed) identifies it as OpenDocument Text |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .odt file?
ODT is the OpenDocument word-processing format, LibreOffice Writer's default and the open, ISO-standardised counterpart to Microsoft's DOCX. Like DOCX it is a zipped bundle of XML, letting any compliant program read and write it without licensing a proprietary spec.
Can Microsoft Word open an ODT file?
Yes, modern Word opens and saves ODT natively. Very complex layouts can shift slightly when converting between ODT and DOCX, so check formatting after converting either way.
What is the difference between ODT and DOCX?
Both are zipped-XML word-processing formats doing the same job. ODT is the OASIS/ISO-standardised open format used by default in LibreOffice, DOCX is Microsoft's own format and the default in Word; each opens in the other's software with generally good, but not always perfect, fidelity.
Comparisons
Related formats
Sources
Details on this page were checked against authoritative references: