HTML → MOBI/AZW3
Converting a novel from HyperText (.html, .htm, .xhtml, .xml, .mhtml) to Kindle / Mobipocket (.mobi, .azw3, .azw) is a routine step in practice — the Kindle format reads natively on Amazon devices and apps, and can be delivered with Send to Kindle. Fortunately HyperText and Kindle / Mobipocket are structurally close, so there is not much to lose. Below we explain in detail how HyperText becomes Kindle / Mobipocket and what to watch out for, and the page ends with a converter that does the job right in your browser — nothing is uploaded, the file never leaves your machine.
What is HTML?
HTML and XHTML are the structural languages of the web, and XHTML is also what EPUB uses internally to hold its content — so converting between HTML and EPUB is essentially a matter of swapping the shell and how assets are packaged. .mhtml goes further and packs a page together with its images and styles into one file, which suits preserving online pages that may disappear. HTML's strength is that it is universal and opens in any browser; its weakness is that styles and images are usually external links, so shipping one self-contained file means inlining them first. Read the HTML format guide
| Extensions | .html.htm.xhtml.xml.mhtml |
|---|---|
| Typical use | Captured web content, EPUB internal content, and a general intermediate representation for other formats. |
What is MOBI/AZW3?
The Kindle family (.mobi, .azw3, .azw) is Amazon's proprietary e-book format. It reflows and can carry a table of contents, and it is read mainly on Kindle devices and the Kindle app, or delivered through Send to Kindle. AZW3 supports a reasonable amount of CSS while the older .mobi barely supports any. It is one of the most common proprietary formats in existing libraries — plenty of books bought or downloaded years ago are in it — which is why converting it to something more portable is such a practical need. Read the MOBI/AZW3 format guide
| Extensions | .mobi.azw3.azw |
|---|---|
| Typical use | Reading on Kindle devices and the Kindle app; one of the most common proprietary formats in existing libraries. |
How to convert HTML to MOBI/AZW3
All structure lives in the tags, but real pages mix in navigation, ads and footers that a naive conversion carries along. Extract the content container first (a readability pass), and note that <img> usually points outside the file — images must be downloaded and embedded before producing a single-file format.
Producing .mobi/.azw3 requires Amazon's toolchain or Calibre. AZW3 supports reasonable CSS while legacy .mobi supports very little; for newer devices, target AZW3 — or simply deliver an EPUB.
Chapter headings in the source are ordinary lines while the target demands a real table of contents. Converters try to match patterns such as "Chapter N"; when the match is poor the TOC is garbled or the book has a single chapter. Check that TOC entries match the actual chapter count.
Convert HTML to MOBI/AZW3
HTML → KINDLE
The Kindle formats (.mobi, .azw3, .azw) are Amazon's proprietary binary containers with no public specification, so they cannot be reliably parsed or produced in a browser. This direction needs a desktop e-book tool; the EPUB or TXT you convert can be read in the Kindle app directly.
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