What Is an ODT File? (And How to Open One on Windows)

An ODT file is an OpenDocument Text document — the word-processing format that LibreOffice, OpenOffice and several other office suites save in by default. If one has landed on your Windows PC and nothing will open it, that is the whole explanation: it is a perfectly ordinary document in a format Windows ships no software for.

The short answer

Convert it. ODT to DOCX if you need to edit it, ODT to PDF if you just need to read or print it. BizTray does both on your own PC with no office suite installed and nothing uploaded.

What the format actually is

ODT is part of the OpenDocument Format family, standardised as ISO/IEC 26300. Under the hood it works much like DOCX: a zip archive containing XML that describes the text, styles and layout, plus the images as ordinary files.

The family covers the obvious siblings:

• .odt — text documents (this one)
• .ods — spreadsheets
• .odp — presentations

Its distinguishing feature is governance rather than technology. ODF is an open standard developed in the open, which is why a number of governments and public bodies mandate it for published documents — the reasoning being that public records should not require a commercial product to read. That is also why ODT files turn up unexpectedly: you downloaded a form from a council or a university.

Why it will not open

Windows includes no software that reads ODT. Neither does a stock install of anything else most people have. The file is fine; there is simply nothing on the machine to open it with.

Modern Microsoft Word can open ODT, and does a reasonable job, though complex layouts and styles can shift. If you already have Word, try it first. If you do not, buying Office to read one attachment is not the answer.

Your options

Convert it. Fastest route, no installation, nothing uploaded. Choose DOCX if you need to edit and send it back, PDF if you need to read, print or file it.

Install LibreOffice. Free and open source, and ODT is its native format, so fidelity is perfect. Worth doing if ODT files reach you regularly. A large download for a one-off.

Ask for a different format. If a person sent it, they can re-export as DOCX or PDF in seconds. If an institution published it, they often offer a PDF version on the same page.

ODT or DOCX — which should you send?

Since this question always follows:

• Send DOCX if you are sending to the wider world. Far more software opens it without a second thought, and "I can't open this" is the response you are trying to avoid.
• Send ODT if you and your recipients are on LibreOffice or OpenOffice, or if you are publishing where an open standard is required or expected.
• Send PDF if the recipient does not need to edit it — which is most of the time, and sidesteps the question entirely.

Converting on your own machine

The Office Converter handles ODT in both directions, and Office to PDF takes it straight to PDF without a DOCX step in between.

Worth knowing:

• The first Office conversion downloads a document engine, about 400 MB, once.
• Conversion is lossy in principle. Text, headings, lists, tables and images come across well; unusual styling can simplify. Check before printing.
• A folder converts in one run, which is the case if you are migrating away from an open-source office suite.
• The original is untouched.

A note on why this is free

BizTray shares a portion of your spare internet bandwidth through a vetted partner rather than charging you. It relays other parties' web traffic and never touches your documents. Sharing is switchable off from Settings or the tray, and the tools do not run while it is off. See How it's funded.

Related

• ODT to DOCX — when you need to edit it.
• ODT to PDF — when you just need to read it.
• How to open a DOCX file — the same problem, other direction.