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Format conversion

FB2 → HTML

Converting a novel from FB2 to HTML: what each format is, what gets lost, the pitfalls for long fiction, and the right tools.

Tide Reader Editorial6 min read

What is FB2?

FB2 (FictionBook 2) is an open XML-based e-book format that is very popular in Russian-speaking regions. Body text, metadata and illustrations all live in one XML file, with images usually embedded as Base64, so a single .fb2 is a complete book that is easy to distribute. It has clean structure and carries chapters and author data natively; the drawbacks are larger size (Base64 inflates images by roughly a third) and less reader support outside Russian-language markets.

Extensions.fb2
Typical useRussian-language e-books; single-file distribution where embedded illustrations and full metadata matter.

What is HTML?

HTML / XHTML is the structural language of the web and is literally the content format inside an EPUB; .mhtml (MHTML) packs a page together with all its resources (images, CSS) into one file, which is what "save as a single page" produces. XML is the general markup language that formats such as FB2 and OPF are themselves written in. The whole family is tagged text where the tags carry the structure, so how much structure survives a conversion depends on how well the tool understands them.

Extensions.html.htm.xhtml.xml.mhtml
Typical useCaptured web content, EPUB internal content, and a general intermediate representation for other formats.

What to watch out for when converting FB2 to HTML

Extracting from the source

FB2 is a single XML file with Base64-embedded images. Parsing must handle the XML namespace and <binary> nodes; ignoring them silently drops every image. Base64 also makes the file roughly a third larger than an equivalent EPUB.

Writing the target format

Whether images and styles are linked or embedded decides if the result travels as one file. To ship a single file, inline the assets as data URIs or use MHTML; otherwise moving the file breaks the images. Keep semantic tags (h1–h6, p) so a later EPUB conversion still yields a table of contents.

Where the two formats interact

  • The source carries real navigation while the target has no concept of chapters, so reading becomes one long scroll. If navigation still matters, keep explicit, uniformly formatted chapter heading lines in the output.

What gets lost

  • Both sides are structurally similar; only fine typographic detail is lost

What you gain

  • Opens in any browser and embeds easily in a web page

Post-conversion checklist

  1. Convert the first three chapters as a trial and check for lost text, interleaved lines or misplaced blocks before doing the whole book.
  2. Jump to five random spots and search a character name to confirm the text is fully searchable.
  3. Confirm illustration count and placement — check that images are not all dumped at the end of a chapter.
  4. Fill in title, author and language — a wrong language tag breaks typesetting such as Chinese line breaking.

Converting novels: what is different

Fiction is the most common and the most peculiar kind of e-book: hundreds or thousands of chapters, almost no figures, often nothing but a TXT source, and Chinese sources that frequently carry anti-piracy garbling. These are the points that bite hardest.

  • A long novel can run to hundreds or thousands of chapters, so the table of contents decides whether the result is usable. Normalise chapter headings to one recognisable pattern first — say "Chapter N Title" alone on its own line — or the target will miss chapters, merge them, or collapse the whole book into one.
  • Volume markers ("Volume One", "Volume Two") usually degrade to ordinary headings, losing the volume/chapter hierarchy. If that matters, promote volume headings one level in an editor afterwards so they are not siblings of chapter titles.

Tools for converting FB2 to HTML

Any of the tools below can handle this direction; pick one by your operating system and how many files you have. Read the previous section first — doing the steps out of order (converting a scanned file before running OCR, for instance) usually means starting over.

Pandoc

FreeCommand line

The Swiss army knife of document conversion, driven by a single command. Its Markdown, DOCX, HTML and EPUB conversions are the highest quality available and it is ideal for authoring-source-to-e-book pipelines. It does not handle MOBI/AZW3 or comic archives.

Platforms: Windows / macOS / Linux (command line)pandoc.org ↗

Calibre

FreeDesktop app

The de-facto standard for e-book conversion, free and open source. It converts EPUB, MOBI, AZW3, PDF, TXT, FB2, DOCX, HTML and nearly everything else, generating tables of contents, fetching metadata and batch-processing whole libraries. The interface is utilitarian, PDF output is mediocre, and the option set takes time to learn.

Platforms: Windows / macOS / Linuxcalibre-ebook.com ↗

SumatraPDF

FreeReader

A lightweight reader for PDF, EPUB, MOBI, CBZ and more that can save PDF content as text. It is a fast way to check whether text extracts cleanly — if the selection comes out garbled, OCR is needed before converting.

Platforms: Windowswww.sumatrapdfreader.org ↗

Common questions

What is lost when converting FB2 to HTML?

Both sides are structurally similar; only fine typographic detail is lost.

Which tool should I use to convert FB2 to HTML?

Recommended: Pandoc, Calibre, SumatraPDF. Pandoc fits this pair best. The Swiss army knife of document conversion, driven by a single command. Its Markdown, DOCX, HTML and EPUB conversions are the highest quality available and it is ideal for authoring-source-to-e-book pipelines. It does not handle MOBI/AZW3 or comic archives.

What should I watch out for when converting FB2 to HTML?

The source carries real navigation while the target has no concept of chapters, so reading becomes one long scroll. If navigation still matters, keep explicit, uniformly formatted chapter heading lines in the output.

Converted it — now what do you read it with?

Tide Reader opens TXT and EPUB, detects chapters on import, lays the text out the way you like it, and syncs your reading position across Windows, macOS, iOS and Android. Drop the converted file in and start reading.

Download Tide Reader

TXT and EPUB; local-first reading, with optional cloud sync and WebDAV.