File formats and compatibility

Writer reads and writes Word’s .docx format directly. This page explains which files it opens, how it saves them, and what is kept and what you can change.

Files Writer opens

Extension	What it is	In Writer
`.docx`	Word document	Opens, edits and saves.
`.docm`	Word macro-enabled document	Opens and edits. Macros are kept in the file and never run.
`.dotx`	Word template	Opens and edits as a document.
`.dotm`	Word macro-enabled template	Opens and edits as a document. Macros are kept and never run.

Writer checks what a file contains as well as its name. A Word document with the wrong extension still opens, and a status bar message says what the file really is.

Files Writer does not open

When Writer can’t open a file, a dialog titled Cannot open followed by the file’s name explains why, with a suggestion underneath. Click OK to close it.

File	Why	What to do
`.doc`, `.dot` — Word 97–2003	This older format is a completely different kind of file, not an earlier version of `.docx`.	Open it in Word once and save it as `.docx`. Writer opens it from then on.
`.odt` — OpenDocument text	It is an OpenDocument file.	Save or export it as `.docx` from the program that made it.
Spreadsheets, presentations and PDFs	Each is for another Nixt Office app. The dialog names it.	Open spreadsheets in Nixt Sheets, presentations in Nixt Slides and PDFs in Nixt PDF.
A file with no extension	Writer can’t tell what it is.	If it is a Word document, rename it to end in `.docx`.
Any other extension, such as `.rtf` or `.pages`	Writer has no editor for it.	Save it as `.docx` from the program that made it.

The file picker on the start screen shows only .docx, .docm, .dotx and .dotm files.

Password-protected documents

When you open a document encrypted with a password in Word, the Cannot open dialog says “This file is not a readable Office package”. Remove the password in Word, save, and open the document in Writer.

A document with restricted editing — read-only, comments only or tracked changes — is different: it opens normally. See Restricting editing.

How Writer saves a document

A .docx file is a package of many parts: the text, styles, numbering, comments, headers and footers, pictures, charts, themes, settings and more. Writer saves with three rules:

Parts Writer doesn’t edit are written back unchanged, byte for byte. That includes charts, embedded fonts, macros, custom XML, glossary and building-block entries, and anything a future version of Word adds.
Paragraphs and tables you didn’t edit are written back exactly as they were read, including everything inside them.
Paragraphs and tables you edited are rewritten from what Writer understands about them.

Styles follow the same idea: only styles you created, redefined or deleted are rewritten. The theme is rewritten only if you choose a new one on the Design tab. Headers and footers are rewritten only if you edit them or add a watermark.

A document created in Writer starts from Word’s standard styles and numbering, so it opens in Word the way it looks in Writer.

What Writer shows, edits and keeps

Feature	In Writer
Text, paragraphs, line and page breaks	Shown, edited and kept
Bold, italic, underline, strikethrough, size, font, colour, highlight	Shown, edited and kept (fonts: see Formatting text)
Superscript, subscript, all caps, character spacing	Shown and kept
Small caps, double and styled underlines	Kept
Theme colours and fonts, including tints and shades	Shown and kept; choose a theme on the Design tab
Alignment, left and right indents, line spacing, space after	Shown, edited and kept
First-line and hanging indents, space before, paragraph shading, keep with next, page break before	Kept (see Paragraphs and styles)
Paragraph styles	Shown; create, redefine, apply and delete; kept
Character and table styles	Character styles shown; both kept
Bulleted, numbered and multi-level lists	Shown, edited and kept
Tables, merged cells, borders, shading, header rows, column widths	Shown, edited and kept (see Tables)
Pictures in line with text	Shown; insert, resize and add alt text; kept
Charts	Shown and kept
Hyperlinks and links to bookmarks	Shown, edited and kept
Bookmarks and cross-references	Shown, edited and kept
Footnotes	Shown, edited and kept
Table of contents	Shown; insert and rebuild; kept
Captions and table of figures	Shown, edited and kept
Citations, sources and bibliography	Shown; add sources, cite and build; kept
Mail merge fields	Shown; insert, preview and merge; kept
Other fields inside a paragraph (for example a date or a document property)	Their last value shown; kept
Headers and footers	Main header and footer shown and edited, with page number, date and file name; kept
First-page and odd/even headers and footers	Used in PDF and print; kept
Comments, replies, resolved state	Shown; add, resolve, reopen and delete; kept
Tracked insertions, deletions, formatting changes and row changes	Shown; record, accept and reject; kept
Tracked moves	Shown; accept and reject; kept
Page size, orientation, margins, columns, page border	Shown, edited and kept
Page colour and text watermark	Shown, edited and kept
Restricted editing	Shown; set and lift; kept
Document properties: title, author, subject	Shown, edited and kept
Macros	Kept, never run
Custom XML, embedded fonts, glossary	Kept

Compatibility with Word

Comments, replies and resolved threads are saved where Word keeps them, so Word shows them as threads.
Tracked changes, including moves and row changes, are saved in Word’s format, signed and dated.
Fields — page numbers, cross-references, captions, citations, merge fields, tables of contents and tables of figures — are real Word fields. Word can update them.
Restrictions set in Writer are honoured by Word, and restrictions set in Word are honoured by Writer.
Pictures you insert are stored with their type, so Word shows them.
A text watermark opens in Word as a watermark.

Export formats

Writer can also save copies as PDF, web page, Markdown and plain text. See Printing and exporting.