CONVERT
EPUB → OPML
Fast, secure EPUB to OPML conversion. No registration required.
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Here is the short version — EPUB is the open IDPF ebook standard, a ZIP of HTML and CSS supported by every modern e-reader. Hence the need for OPML. A EPUB to OPML conversion turns an ebook into an editable or printable document. Instead of a stream that reflows to any screen, you get a OPML with deliberate page breaks, headers, footers and margins — suitable for PDF export, print-on-demand or further editing. Keep in mind EPUB is the open IDPF ebook standard, a ZIP of HTML and CSS supported by every modern e-reader. And remember that OPML is a document format oriented around a particular office suite or publishing pipeline.
EPUB eBook
Source formatEPUB is the open standard for reflowable digital books. It adapts text to any screen size and is supported by most e-readers except Kindle. EPUB 3 adds support for multimedia and interactivity.
OPML Outline
Target formatOPML (Outline Processor Markup Language) is an XML format for structured outlines and lists. It is most widely used for exchanging RSS feed subscription lists between podcast apps and feed readers, and for hierarchical note-taking.
Why convert EPUB to OPML
Retailers and printers often demand OPML submissions rather than EPUB. Converting up front gives you control over the pagination and styling rather than leaving it to their automated ingest pipeline.
HOW TO CONVERT
EPUB → OPML
Provide the EPUB
Drag-and-drop the ebook up to 100 MB. No account required on the free tier.
Rewrite to OPML
The pipeline preserves heading structure, lists and images while adding page geometry the OPML expects.
Retrieve the output
Click to download the OPML. Open it in Word, LibreOffice or any document editor.
Common Use Cases
Translation workflows
CAT tools parse OPML natively but may stumble on EPUB packaging; convert to simplify the pipeline.
Back-cover and marketing extract
Pull a clean OPML of one chapter to use as marketing sample from a full-book EPUB.
Compliance archival
Regulated industries archive final-form OPML with PDF/A downstream — start from EPUB and produce the paper-trail OPML.
Library ingestion
Some institutional repositories ingest OPML only; repurpose existing EPUB holdings instead of requesting new submissions.
EPUB vs OPML — Strengths and limitations
What each format does best, and where it falls short.
EPUB Strengths
- Open standard — no vendor lock-in, no DRM required.
- Reflowable text — adapts to any screen size, font size, or orientation.
- Rich typography via CSS, embedded fonts, and SVG.
- Accessibility-first: native support for screen readers, adjustable text, and alt-text.
- Universal across every non-Kindle ebook reader and library app.
Limitations
- Kindle does not support EPUB natively (Amazon wants you to convert to AZW3).
- Fixed-layout EPUBs (for children's books, comics) are awkward to author.
- Rendering quality varies between apps — some CSS works everywhere, some does not.
OPML Strengths
- Standard RSS subscription interchange format.
- Simple XML — easy to parse and generate.
- Highly extensible via arbitrary attributes.
- Supported by every major outline and RSS tool.
Limitations
- XML verbosity — larger than a JSON-based equivalent.
- Specification is loose — different tools disagree on edge cases.
- Primary use (RSS reading) has shrunk dramatically since Google Reader.
EPUB vs OPML — Technical specifications
Side-by-side comparison of the technical details.
| Specification | EPUB | OPML |
|---|---|---|
| MIME type | application/epub+zip | text/x-opml |
| Extension | .epub | .opml |
| Container | ZIP archive | — |
| Markup | XHTML 1.1 (EPUB 2); HTML5 (EPUB 3) | — |
| Standards | IDPF/W3C EPUB 2.0.1, 3.0, 3.2, 3.3 | — |
| Format | — | XML with nested <outline> elements |
| Standard | — | OPML 2.0 (2006) |
| Primary use | — | RSS subscription interchange |
EPUB vs OPML — Typical file sizes
Approximate file sizes for common scenarios.
EPUB
- Novel (300 pages, text only) 200-800 KB
- Illustrated reference book 5-30 MB
- Fixed-layout children's book 30-100 MB
OPML
- Typical RSS reader export (50 feeds) 5-30 KB
- Deep outline (Scrivener novel plan) 20-200 KB
Quality & Compatibility
Images re-embed at their original resolution; vector figures convert to PNG where the OPML does not support vector primitives. Tables maintain row/column structure but simple layouts travel better than complex nested grids.
Tips for Best Results
- Set page size (A4 vs Letter vs 6x9 trim) explicitly in Advanced when producing a print-ready OPML — the default is A4.
- If chapter breaks disappear in the OPML, enable "force section break before H1" in Advanced to insert a hard page boundary at every chapter.
- Keep the EPUB original; future-proofing your manuscript means always being able to regenerate downstream formats.
Frequently Asked Questions
Frequently Asked Questions
Yes. The free tier accepts files up to 100 MB without registration, email capture or watermarks. Paid plans raise the size cap, enable batch conversions and provide a REST API for automation, but nothing on the free tier is quality-limited — the output is exactly the same as on any paid plan.
Yes when the source EPUB tags chapter starts semantically (H1 / section boundaries). Each chapter becomes a new section in the OPML with a page break before it. If the EPUB uses only visual cues like larger font sizes, enable "detect chapters heuristically" in Advanced so we still produce clean breaks.
Uploads run over HTTPS, files are processed in isolated containers, and both the source EPUB and the OPML output are auto-deleted within two hours. No account is required, file contents are never logged, and KaijuConverter does not use uploads for AI training. The paid plan adds a signable data-processing agreement for regulated workflows.
Yes. The cover from the EPUB becomes the first page of the OPML (or is moved to metadata depending on document conventions). Inline images re-embed at their source resolution; you can toggle "optimise images" in Advanced to shrink the OPML file size.
Most files finish in well under a minute. Small images and documents are typically ready in a few seconds; large video or audio files scale roughly with duration. Upload speed from your network is usually the dominant factor, not server time.
Yes. We produce a clean OPML with paragraph and heading styles mapped to standard document styles. Open it in Word, LibreOffice or Google Docs and you can edit, comment and track changes just like any native document.
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Related Guides
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Read guideEPUB Format: Electronic Publication Ebook Standard — Complete Guide
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.