DOCX to MOBI Converter

DOCX to MOBI — Or Should You Make an EPUB Instead?

MOBI turns a Word document into a reflowable ebook that adapts to any screen, with chapter navigation instead of fixed Letter-size pages. Before you convert, know that MOBI is Amazon's legacy format: Amazon moved Send to Kindle away from MOBI in late 2022 in favour of EPUB, which it converts to a modern Kindle format on delivery. So the honest short answer is this — if you want to get a new book onto a current Kindle, convert to EPUB. Choose MOBI when you specifically need the older format: an older reader, an existing MOBI library, a tool or catalogue that expects .mobi, or a device that never adopted EPUB.

MOBI vs EPUB Side by Side

When MOBI Is Still the Right Choice

• You are feeding a MOBI-only library manager or an older cataloguing tool.
• You have an early Kindle or a non-Amazon reader from the Mobipocket era that reads .mobi and nothing newer.
• You are matching the format of an existing collection so everything stays consistent.
• A publishing workflow or submission process you do not control still asks for .mobi.

When to Convert to EPUB Instead

• You want to send the book to a current Kindle wirelessly — that path is EPUB now.
• The book should also open on Kobo, Apple Books, Google Play Books, or Nook.
• You are producing something new and want a format that is still maintained.
• You plan to submit to an ebook store, where EPUB is the expected deliverable. Use DOCX to EPUB.

How to Convert DOCX to MOBI

1. Upload Your DOCX File: Drag your .docx onto the page or click "+ Add Files" to browse. Queue several manuscripts to convert them in one batch, each producing its own .mobi.
2. Leave the Settings Alone: There is nothing to tune on this conversion — the output format is fixed and the conversion defaults are already set for clean, navigable ebook output. Your document's structure does the real work.
3. Style Chapters With Heading 1 First: Before uploading, make sure chapter titles use Word's built-in Heading 1 style (and Heading 2 for sub-sections), and set every image to In Line with Text. Heading styles are what become the ebook's chapter navigation; bold text at a larger size is treated as an ordinary paragraph.
4. Convert and Download: Click Convert and save your .mobi. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared or made public.

What Carries Over From Word

Frequently Asked Questions

Can I still send a MOBI file to my Kindle?

Not through Send to Kindle — Amazon moved that service off MOBI in late 2022 and now takes EPUB, converting it to a Kindle format on its own side. Copying a .mobi over USB still works on devices that read it, and MOBI files already in your library keep working. For wireless delivery of anything new, convert to EPUB instead.

Is MOBI the same thing as AZW or AZW3?

They are closely related but not identical. The original Kindle AZW format was based on Mobipocket's, differing mainly in how the serial number is represented. AZW3, also called KF8, arrived in late 2011 with the Kindle Fire and supports far more HTML and CSS; it was built as a container that can also carry backward-compatible MOBI content. So MOBI is the ancestor of the Kindle formats rather than a synonym for them.

Why is MOBI considered obsolete?

Because its owner moved on. Amazon shut down the Mobipocket website and servers on 31 October 2016, replaced the format with KF8/AZW3 for its own devices, and then moved Send to Kindle to EPUB. MOBI's rendering is also limited by modern standards — it predates the HTML and CSS features that current ebook layouts rely on, so complex formatting degrades more than it would in EPUB.

Will my Word formatting carry over?

Headings, bold and italic, lists, and inline images carry across, and Word heading styles become the ebook's chapter navigation. Because MOBI is reflowable, anything tied to a fixed page does not translate: page size, margins, headers and footers, precise columns, and footnotes anchored to the bottom of a printed page. If preserving exact layout is the point, convert to PDF instead.

How do I get a working table of contents?

Structure the document with Word's built-in Heading 1 and Heading 2 styles rather than manually enlarged or bolded text. Those heading levels are read to build the ebook's logical table of contents, which is what a reader uses for chapter navigation. Text that merely looks like a heading is treated as a normal paragraph and will not appear.

Should I convert to MOBI or to EPUB for a brand-new book?

EPUB, in nearly every case. It is the actively maintained open standard, it is what Send to Kindle accepts, it is what ebook stores expect, and it opens on non-Kindle readers as well. MOBI is worth choosing only when something specific in your workflow requires the older format. Both start from the same Word file, so you can produce DOCX to EPUB as well and keep whichever you need.

Is my document converted by way of a PDF?

No. The Word file is read directly as a word-processor document, which is what allows headings, lists, and emphasis to survive as real ebook structure. Routes that flatten a document to PDF pages first and then rebuild the text are where jumbled paragraphs and missing chapter navigation usually come from.

Is there a limit on document size?

There is no page or word-count cap; the practical constraint is the upload itself and how quickly your connection sends it. Most manuscripts are a few megabytes even with images. Bear in mind that MOBI is an inefficient container for image-heavy books, so an illustrated document can produce a noticeably larger ebook than the same content as EPUB.

I already have an EPUB — do I need to start from Word again?

No. If you have a finished EPUB you are happy with, EPUB to MOBI converts it directly. Starting from your clean Word source is generally better when you have it, since each conversion works from the structure it is given, and a well-styled DOCX carries more reliable heading information than an EPUB that was itself converted from something else.