How do I convert EPUB to MOBI?

Upload your EPUB, choose MOBI as the output (or pick a Kindle device preset), and click Convert. The tool reads the EPUB’s chapters, metadata and cover and writes a Kindle-readable MOBI with EXTH metadata and an embedded cover — all on your device.

How do I convert MOBI to EPUB?

Upload your MOBI (or AZW/PRC), choose EPUB as the output, and Convert. The MOBI’s PalmDOC text records and EXTH metadata are decoded and rebuilt into a clean EPUB 3 with a navigation document and NCX so it works on Kobo, Apple Books and other readers.

How do I convert EPUB to AZW3?

Choose AZW3 (or a Kindle preset). AZW3 (KF8) is Amazon’s proprietary container; true KF8 generation is offered through our API. The browser tool delivers a Kindle-compatible MOBI instead, which every modern Kindle and the Kindle app open — so your book still works on Kindle.

How do I convert PDF to EPUB?

Upload the PDF and choose EPUB. The converter extracts the text page-by-page with pdf.js, reflows it into chapters, strips repeated headers/footers and rebuilds it as a reflowable EPUB. For scanned PDFs, enable OCR to turn the page images into searchable text first.

How do I convert PDF to MOBI?

Upload the PDF, pick MOBI (or a Kindle preset) and Convert. The text is extracted and reflowed, then written as a Kindle-readable MOBI. Reflowed text reads far better on Kindle than a fixed-layout PDF.

Is this eBook converter free?

Yes. Converting between EPUB, MOBI, PDF, DOCX and the other supported formats is free with no sign-up, no watermark and no daily limit. A developer API is available for automated and high-volume conversion.

Are my books uploaded to a server?

No. The entire conversion runs in your browser using JavaScript — your book is read, converted and offered back as a download without ever leaving your device. The only exception is PDF output, which can use our Chromium rendering service for the highest fidelity (with an in-browser fallback).

Which input formats are supported?

EPUB, MOBI, AZW, AZW3, PRC, PDB, PDF, DOCX, ODT, TXT, HTML, Markdown, RTF, FB2 and CBZ comics are read in the browser. KFX, CBR, DjVu, CHM and LRF are proprietary or need extra codecs and are offered via the API.

Which output formats are supported?

EPUB, MOBI, PDF, DOCX, TXT, HTML, FB2 and RTF are generated entirely in the browser. AZW3 (KF8) is delivered as a Kindle-compatible MOBI in the browser, with true KF8 available via the API.

Does it work on Kindle?

Yes. Convert to MOBI for universal Kindle support across every generation, or use the Kindle device presets (Paperwhite, Oasis, Scribe). Modern Kindles also accept EPUB via Send-to-Kindle, so EPUB output works on recent devices too.

Does it work with Kobo?

Yes. Kobo readers use EPUB natively. Choose EPUB output or a Kobo device preset (Clara, Libra, Sage) and the book is tuned for Kobo screens and reflow.

Does it work with Apple Books?

Yes. Apple Books uses EPUB. Pick EPUB or an Apple device preset (iPad, iPhone) and the output is optimised for Apple Books.

What is the difference between EPUB, MOBI and AZW3?

EPUB is the open, universal standard used by Kobo, Apple Books, Google Play Books and modern Kindles. MOBI is Amazon’s older Kindle format, supported by every Kindle generation. AZW3 (KF8) is Amazon’s newer format with richer CSS support. For maximum compatibility convert to EPUB; for older Kindles convert to MOBI.

What is the best format for Kindle?

For older Kindles, MOBI is the safest choice. For Kindles from roughly 2022 onward and the Kindle app, EPUB works via Send-to-Kindle and AZW3/KF8 gives the best formatting. This tool produces MOBI directly and Kindle-compatible files, plus EPUB for newer devices.

Will my metadata be preserved?

Yes. Title, author, publisher, language, ISBN, publication date, series, description and subjects are read from the source and written into the output. You can also edit any field in the built-in metadata editor before converting.

Can I edit the metadata?

Yes. The metadata editor lets you change the title, author(s), publisher, ISBN, language, series and index, description, copyright and tags. Your edits are written into the converted file’s metadata (OPF for EPUB, EXTH for MOBI, core.xml for DOCX, etc.).

Can I change or add a cover?

Yes. Extract the existing cover, upload a custom image, generate a cover from the title and author, convert it to grayscale for e-ink, or remove it. The cover is embedded in the output (EPUB cover image, MOBI cover record, FB2 binary).

Does it keep the table of contents?

Yes. The source TOC (EPUB nav/NCX, MOBI navigation, detected chapters) is preserved, and you can have the tool generate a fresh multi-level TOC with chapter navigation and bookmarks if one is missing.

Can it detect chapters automatically?

Yes. For PDFs, TXT and other flat formats, the converter detects chapter boundaries from headings and “Chapter” markers and builds a navigable TOC, so your converted EPUB/MOBI has proper chapter navigation.

Can I convert a scanned book with OCR?

Yes. When a PDF has no extractable text (a scanned book), enable OCR and the pages are recognised with tesseract.js into searchable text. OCR supports English, Hindi, Arabic, French, German, Spanish, Chinese, Japanese, Russian, Portuguese and Italian.

Which OCR languages are supported?

English, Hindi, Arabic, French, German, Spanish, Chinese (Simplified), Japanese, Russian, Portuguese and Italian, powered by tesseract.js which loads on demand only when OCR is enabled.

Can it convert comic books (CBZ)?

Yes. CBZ comic archives (a ZIP of images) convert to EPUB, PDF or MOBI as image-based books. Enable Manga/RTL mode for right-to-left reading order. CBR (RAR-based) needs the API — re-save it as CBZ to convert in the browser.

Does it support manga and right-to-left reading?

Yes. Turn on Manga / RTL reading and the output sets a right-to-left page-progression direction so comics and manga read in the correct order on your device.

Can I convert several books at once?

Yes. Add as many books as you like; they are queued and converted one after another, each with its own progress, validation and download. Download them individually or all together as a ZIP.

Can I edit metadata for many books at once?

Each book has its own metadata editor so you can tailor every title; batch conversion then applies your global format and typography settings across the whole queue.

How long does conversion take?

Most books convert in a second or two. PDFs take longer because the text is extracted page-by-page, and OCR is slower still because each page is recognised. A live progress dashboard shows the current stage and percentage.

Is there a file-size limit?

Because conversion happens in your browser, the practical limit is your device’s memory rather than a server cap. Large textbooks and 1000+ page books convert fine on a desktop; very large or image-heavy books are slower on phones.

Does converting reduce quality?

Text is preserved exactly and reflows cleanly. Images can be kept at full quality, optimised (resized and recompressed), converted to grayscale for e-ink, or removed — your choice. High Quality and Archive modes preserve the most detail.

Can I optimise images for e-readers?

Yes. Choose Optimize to resize images to your device’s screen width and recompress them (smaller files), or Grayscale to convert them for e-ink screens, which dramatically reduces size for Kindle and Kobo.

What does the validation report check?

It checks EPUB structure, metadata completeness, table of contents, image alt text (accessibility), cover presence, DRM status and Kindle compatibility, and gives a clear list of errors and warnings with fixes before you convert.

Does it check Kindle compatibility?

Yes. The validator flags issues that affect Kindle — missing cover, image-heavy MOBI size, EPUB-vs-MOBI choice for older devices — so your converted book displays correctly on Kindle.

No. This tool detects DRM and tells you when a book is protected, but it does not and will not remove DRM. You can only convert books you own that are DRM-free. For protected books, download a DRM-free copy from the retailer where possible.

How do I know if my book has DRM?

When you upload a book, the analysis shows a DRM badge if encryption is detected (an EPUB encryption.xml or an encrypted MOBI). DRM-protected text cannot be converted; only the metadata and cover are recoverable.

What is the reading time estimate?

After analysing a book, the tool shows an estimated reading time based on its word count at about 220 words per minute, along with the page and chapter counts — handy for planning your reading.

Can I preview the book before converting?

Yes. The built-in reader shows the cover, a chapter list and the formatted content in desktop, tablet, mobile or Kindle-style frames, so you can check the result before and after conversion.

Yes. For EPUB output you can embed fonts so typography is consistent across devices. You can also choose a reading font (serif, sans, monospace or a high-legibility face) applied during conversion.

Can I change the font and spacing?

Yes. Set the font family, font size, line height, paragraph spacing, margins, justification and hyphenation. These are written into the output’s stylesheet so your reader displays the book exactly as configured.

Is it accessible (a11y)?

The converter preserves and generates semantic structure (headings, navigation) and flags missing image alt text and language metadata in the validation report, helping you produce accessible EPUBs that work with screen readers.

Does it support EPUB 2 and EPUB 3?

Yes. Choose EPUB 3 (with a navigation document) for modern readers, or EPUB 2 (with NCX and a guide) for maximum compatibility with older devices. Both include an NCX for broad support.

Can I convert DOCX to EPUB?

Yes. Upload a Word .docx and choose EPUB (or MOBI). The document is parsed with mammoth into clean HTML, split into chapters by heading, and rebuilt as an EPUB with a table of contents.

Can I convert TXT to EPUB?

Yes. Plain-text books are paragraph-detected and chapter-split (on “Chapter” markers and headings) and rebuilt as a navigable EPUB or MOBI with proper structure.

Can I convert HTML to EPUB?

Yes. An HTML file is parsed, split into chapters at headings, and packaged as an EPUB with images inlined. It’s ideal for turning web content or generated HTML into a proper eBook.

Can I convert Markdown to EPUB?

Yes. Markdown is converted to HTML (headings, lists, bold/italic, code, links) and then packaged as an EPUB or MOBI with chapter navigation.

Can I convert FB2 to EPUB or MOBI?

Yes. FictionBook (FB2) files are parsed for metadata, cover (embedded base64) and sections, then rebuilt as EPUB, MOBI or any other supported output.

Can I convert an eBook to PDF?

Yes. Any supported book converts to PDF using a real Chromium rendering engine for crisp, vector text (with an in-browser fallback). Choose a page size like A5, 6×9 or Kindle and the book is laid out for reading or printing.

Can I convert an eBook to Word (DOCX)?

Yes. Convert to DOCX to get an editable Word document with headings and paragraphs preserved — useful for editing or repurposing a book’s text. (Images are omitted from DOCX; use EPUB or PDF to keep images.)

Can I convert an eBook to plain text?

Yes. TXT output extracts the clean reading text with chapter separators — perfect for analysis, archiving or importing elsewhere.

Does it keep links and footnotes?

Internal and external links in the source are preserved in EPUB and HTML output. Footnotes are kept as part of the text; complex interactive footnote popups are simplified to inline references.

What happens to images in MOBI output?

Inline images and the cover are embedded as MOBI image records and referenced by recindex, so they display on Kindle. Optimise images to keep the MOBI file size reasonable for image-heavy books.

Why is my converted MOBI large?

Image-heavy books produce large MOBIs because each image is embedded. Use the Optimize or Grayscale image setting and lower the maximum image width to shrink the file substantially.

eBook Converter

Convert EPUB, MOBI, AZW3, PDF, DOCX and more — optimised for Kindle, Kobo and Apple Books. Edit metadata and covers, run OCR, validate compatibility and preview, all privately in your browser. No watermark, no sign-up.

EPUB · MOBI · AZW3 · PDF100% privateNo watermark

EPUB · MOBI · AZW3 · PDF · DOCX · FB2 & more100% private — runs in your browserMetadata · cover · OCR · validation

Drag & drop your eBook

or browse, upload a folder, or import from a URL

EPUB, MOBI, AZW/AZW3, PDF, DOCX, ODT, TXT, HTML, MD, RTF, FB2, CBZ & more

Your library is empty. Add an EPUB, MOBI, PDF or other eBook above — everything is processed privately on your device.

Why this is the best free eBook converter

Every major format

EPUB, MOBI, AZW/AZW3, PDF, DOCX, ODT, TXT, HTML, Markdown, RTF, FB2 and CBZ comics — read and convert between them.

100% private

Real EPUB and binary MOBI engines run in your browser. Your books are never uploaded; DRM is detected, never removed.

Device presets

One-click tuning for Kindle Paperwhite/Oasis/Scribe, Kobo Clara/Libra/Sage, iPad, iPhone and Android.

Metadata & cover

Edit title, author, series, ISBN and description; extract, replace, generate or grayscale the cover before converting.

OCR & comics

Make scanned PDFs searchable with multi-language OCR, and convert CBZ comics with manga / right-to-left reading.

Validate & preview

Compatibility & accessibility validation plus a built-in reader with desktop, tablet, mobile and Kindle views.

What is an eBook converter?

An eBook converter transforms a digital book from one file format to another so it opens and reads correctly on your device or app. The common jobs are EPUB to MOBI (for Kindle), MOBI to EPUB (for Kobo and Apple Books), PDF to EPUB (to make a fixed PDF reflow), and conversions to and from DOCX, TXT, HTML, FB2 and RTF.

This converter works by parsing each source format into a single structured model — metadata, cover, chapters, table of contents and images — and then rebuilding that model in your chosen output format. Everything runs in your browser: EPUB is unzipped and its OPF/NCX parsed, MOBI’s binary PalmDB records are decoded, PDFs are read with pdf.js, and the result is written back out as a valid EPUB, a Kindle-readable MOBI, a print-ready PDF, and more.

Why convert eBooks?

Converting a book to the right format unlocks better reading everywhere. The most common reasons:

Device compatibility — get the right format for Kindle, Kobo, Apple Books or Google Play Books.
Better reading experience — reflowable EPUB/MOBI beats a fixed PDF on small screens.
Kindle support — convert EPUB to MOBI so any Kindle can read your book.
Kobo & Apple support — convert MOBI/AZW3 to EPUB for non-Amazon readers.
Smaller files — optimise or grayscale images for e-ink and faster transfers.
Better typography — choose fonts, spacing and margins tuned to your eyes and screen.

Convert an eBook in 3 steps

Upload your eBook

Drag in an EPUB, MOBI, AZW3, PDF, DOCX or other supported file (or import from a URL). The tool instantly analyses it — title, author, cover, chapters, word count, reading time and DRM status — entirely in your browser.

Choose output & options

Pick an output format (EPUB, MOBI, PDF, DOCX…) or a one-click device preset for Kindle, Kobo or Apple Books. Edit metadata, swap the cover, tune typography and images, then validate compatibility.

Convert & download

Press Convert. Watch the live progress dashboard, preview the result in a built-in reader, then download the book, share it, or grab a whole batch as a ZIP.

EPUB vs MOBI vs AZW3

These are the three formats people convert between most. EPUB is the open universal standard; MOBI is Amazon’s older Kindle format with the widest Kindle support; AZW3 (KF8) is Amazon’s richer modern format. The table below compares what matters when you choose an output.

Feature	EPUB	MOBI	AZW3
Kindle compatibility	Modern Kindles (Send-to-Kindle)	All Kindle generations	Modern Kindles (best CSS)
Kobo / Apple / Google	Native, universal	Not supported	Not supported
Formatting / CSS	Rich (EPUB3)	Basic	Rich (KF8)
File size	Compact	Larger	Larger
Reflowable text	Yes	Yes	Yes
Accessibility	Strong (semantic + nav)	Limited	Good
Best for	Everything except old Kindles	Older Kindles	Newer Kindles, rich layout

Best format for Kindle

For the broadest Kindle support — including older devices — convert to MOBI. Every Kindle generation reads MOBI, and this tool writes a proper MOBI with embedded cover and metadata.

For Kindles from around 2022 onward and the Kindle app, EPUB works through Amazon’s Send-to-Kindle, and AZW3 (KF8) gives the richest formatting. True AZW3/KF8 generation is available via our API; in the browser the AZW3 option delivers a Kindle-compatible MOBI so your book still works on Kindle.

Supported input formats

EPUBEPUB 2 & 3

MOBIAll Kindle

AZW / AZW3Kindle

PDFText + OCR

DOCXWord

ODTOpenDocument

TXTPlain text

HTMLWeb

Markdown.md

RTFRich text

FB2FictionBook

CBZComics

Supported conversion matrix

Convert any source on the left into any of the targets on the right.

EPUBMOBIAZW3PDFDOCXTXTHTMLFB2RTF

MOBIEPUBPDFDOCXTXTHTMLFB2

AZW / AZW3EPUBPDFDOCXTXT

PDFEPUBMOBIDOCXTXTHTML

DOCXEPUBMOBIPDFTXTHTML

TXTEPUBMOBIPDFHTMLFB2

HTMLEPUBMOBIPDFDOCXTXT

FB2EPUBMOBIPDFTXT

CBZEPUBPDFMOBI

Privacy, DRM & data handling

Your books are private. The conversion runs entirely in your browser — your file is read, converted and downloaded without ever being uploaded (the only optional exception is high-fidelity PDF output via our Chromium service, which processes content in memory and deletes it immediately).

This tool detects DRM and clearly reports protected books, but it does not and will not remove DRM. You can convert only DRM-free books that you own. Files are never stored on our side, which keeps the workflow GDPR-friendly by design.

eBook conversion API

Automate conversion at scale with the eBook Conversion API: EPUB, MOBI, AZW3/KF8, PDF and more, batch and asynchronous jobs, webhooks, API keys, team accounts, usage analytics and a device-optimisation endpoint.

Pricing scales from a Free tier for prototyping to Pro, Business and Enterprise plans that add true AZW3/KF8 output, certified PDF/A, OCR, the proprietary input formats (KFX, CBR, DjVu, CHM, LRF where rights allow) and SLA-backed support.

Free

$0/mo

100 conversions / mo
EPUB · MOBI · PDF · DOCX
Metadata & cover tools
Community support

Start free

Popular

Pro

$15/mo

10,000 conversions / mo
AZW3/KF8 & PDF/A
Async jobs & webhooks
OCR included

Go Pro

Business

$59/mo

100,000 conversions / mo
KFX/CBR/DjVu inputs
Team accounts & API keys
Usage analytics

Choose Business

Enterprise

Custom

Unlimited volume & SLA
Device-optimisation API
Library batch automation
Dedicated support

Contact sales

Frequently Asked Questions

An eBook converter changes a digital book from one format to another — for example EPUB to MOBI, MOBI to EPUB, PDF to EPUB or AZW3 to EPUB — so it opens correctly on your device or app. This converter parses the source book into a structured model (metadata, cover, chapters, table of contents) and rebuilds it in the target format, entirely in your browser. Nothing is uploaded.

Troubleshooting guide