eBook Converter: EPUB, MOBI, AZW3 + Metadata Editor

About

eBook Converter converts EPUB to MOBI, EPUB to AZW3, MOBI to EPUB, AZW3 to EPUB and other common ebook pairs directly in your browser. Edit metadata and covers, and keep a local library of imported books. No desktop install and no account required.

Typical use cases: converting an EPUB for printing, reflowing a document for comfortable reading, or preparing a book for a Kindle (legacy or modern). Going the other way — off a Kindle back to EPUB — is useful when switching to a Kobo, PocketBook or Boox. Legacy ebook formats and common document inputs are also supported.

✨ What's included

• Multi-format converter. 17 input formats and 7 output formats in one extension.
• Built-in metadata editor. Edit title, author, series and number, publisher, published date, ISBN, language (ISO 639-1), tags and description before you export. The original file is left untouched.
• Cover editor. Add or replace a book cover in a couple of clicks.
• Kindle-optimized presets. Dual KF7 + KF8 output, e-ink-friendly typography, and image handling tuned for Paperwhite, Oasis and Scribe.
• Side Panel UX. Uses the modern Chrome 114+ side panel, so the converter stays docked next to your active tab rather than floating in a popup.
• Persistent library. Imported books, covers and metadata are stored locally in IndexedDB and survive between browser sessions. Search, sort and bulk-convert a selection in one queue.
• Privacy-aware processing. Formats a browser can read are parsed entirely on your device and never uploaded. Formats that only the Calibre engine can read are streamed through our service and deleted immediately — no storage, no content logs.
• Light, dark and system themes. No account, no subscription, no watermark.

❓ FAQ

Can I convert to a Kindle format without installing Calibre?
Yes. The extension uses the Calibre engine server-side, so you get the same conversion quality without a desktop install.

Is there a paid tier?
There is no paid tier, no account and no watermark. A daily quota per IP protects the service from abuse and covers normal personal use.

Does the extension upload my books to a server?
Only the formats a browser cannot parse on its own. Everything the browser can read is handled locally; legacy and Kindle formats that require the Calibre engine are streamed through our service and deleted immediately. Nothing is stored or logged.

Can I edit the metadata of an existing EPUB file?
Yes. Open the metadata editor, change what you need, and export. The original file is not modified.

Will Kindle accept the output?
Yes. The Kindle preset produces dual-format MOBI files suitable for Send-to-Kindle and sideloading on Paperwhite, Oasis, Scribe and earlier Kindle devices.

Will FB2 work for a Russian-language library?
Yes. FB2 and FBZ input are supported, and the original encoding (including Windows-1251) is detected automatically, so Cyrillic text renders correctly in the resulting EPUB.

Install the extension and convert your first book in under a minute.