How to open a Word document without Word, and without uploading it

Open the .docx in Docs, with Open or by dropping it on the page. The headings, paragraphs, bold, italic, lists, tables, links, footnotes and pictures come across into an editor; change what you like; Save to computer writes it back as a .docx that Word, LibreOffice and Pages open, and Print / PDF gives a PDF. There is no account and nothing is uploaded; the page works with the network off. What Word keeps that has no equivalent here (tracked changes, comments, fonts, columns, page layout) does not come across, and this page says so.

What a .docx actually is

Not a Word file in any deep sense. A .docx is a zip; inside it, the words are in one XML file, the pictures are files beside it, and the rest is styling, numbering and bookkeeping. Word reads that zip; so does LibreOffice, so does Pages, and so can a browser, which already has an XML parser and a zip library. The converter websites are running one of those on a server, which is why they need the file uploaded. It is not a necessary part of the job.

What comes across

• The words, with their paragraphs and their headings by level.
• Bold, italic, strike-through, superscript and subscript. Underline is not carried across, because Word documents use it mostly for links, which are.
• Bulleted and numbered lists, nested.
• Tables, as tables.
• Links, kept as links, and footnotes, as numbered notes at the end.
• Pictures, kept in the document.

What does not

This is the part a comparison page usually leaves out.

• Tracked changes and comments. The editor has neither. A document with changes waiting for review arrives with the changes applied and the comments gone; review it in a program that has them, or ask for a clean copy. REDLINE on this site compares two versions if that is what is needed.
• Fonts, colours as a theme, and Word's page. Word's fonts, margins, columns, headers and footers, page breaks and section breaks do not come across. The page here is set in Page setup instead (A4 or Letter, portrait or landscape, the margins, a header and a footer on every printed sheet), page breaks are put in here, and the .docx written back carries that paper and those margins with the editor's own plain styles.
• Text boxes, shapes, charts and SmartArt. The words in a text box come through where they can; the box does not.
• Macros and fields. A field shows its last value; a macro is not carried, which is also the safe answer.

Saving it back

Save to computer writes a .docx from what is in the editor: headings, paragraphs, emphasis, lists, tables, links and pictures, editable in Word and everything that reads Word. Print / PDF gives the document as a PDF through the browser's own print, with no watermark. Either can be saved into a folder on your disk.

What the file may be carrying

A .docx often holds more than the page shows: the author's name and organisation, the edit time, the template it was made from, and sometimes the tracked changes and comments that were "removed" but not accepted. DOCSCRUB shows what a Word file carries and strips it. If the question is whether a file is safe to open at all, DISARM takes the macros and the active content out first.

The short version