MOBI Converter

How to Convert a MOBI File

1. Upload Your MOBI File: Drag your .mobi into the drop zone or click "Add Files". Add several at once and each book converts in turn, which is the usual case when someone is migrating a whole Kindle-era shelf.
2. Pick an Output Format: The eBook File Extension selector on this page offers EPUB and MOBI, with EPUB preselected — that is the open standard every current e-reader accepts. There are no quality settings to choose: an ebook conversion re-writes document structure rather than re-encoding a media stream.
3. Check the File List: Drop anything you added by accident and make sure each file is a DRM-free copy. A book still wrapped in store DRM cannot be converted by any format converter, so it is worth confirming before you start rather than after.
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, converted on our servers with Calibre's ebook-convert engine, and deleted automatically after a few hours — no sign-up, no watermark, never shared.

Popular MOBI Conversions

• MOBI to EPUB — the open standard that current Kindle, Kobo, Apple Books and Play Books all read
• MOBI to PDF — a fixed-layout copy for printing or annotating; this target has its own tool page rather than sitting in the selector above

Going the other way, EPUB to MOBI produces a legacy Kindle file for older hardware and PDF to MOBI starts from a document instead of a book. The EPUB converter hub covers the open-standard side in full.

Why Convert a MOBI File?

MOBI is the Mobipocket format. Mobipocket SA was founded in Paris in March 2000 by Thierry Brèthes and Nathalie Ting, building a reader for phones and PDAs on top of a record-based file structure inherited from the Palm Database format. Amazon bought the company in 2005 and made MOBI the technical foundation of the Kindle: the original AZW format that shipped with the first Kindle in 2007 was Mobipocket with Amazon's own serial-number handling. Amazon then moved on — AZW3 (Kindle Format 8) arrived with the Kindle Fire in late 2011 with a subset of HTML5 and CSS3, KFX followed in August 2015 with a new typesetting engine, and the Mobipocket website and servers were shut down permanently on 31 October 2016.

What that leaves is a format with no living specification, no vendor behind it, and a shrinking set of readers. Converting forward is the point:

• To read it on anything current, convert to EPUB. EPUB is the open W3C standard, it reflows to any screen and font size, and current Kindle, Kobo, Apple Books, Google Play Books and essentially every reader app open it. This is the right target if the goal is simply to read the book again.
• To print or annotate it, convert to PDF. A fixed page is what you want for marking up, printing, or sending a copy that must look identical everywhere. It is a poor reading experience on a phone, and an excellent one on paper.
• To keep a library readable, migrate it now. MOBI is not maintained by anyone. Each year fewer apps bother implementing it, and there is no standards body that will keep it alive. Moving a collection to EPUB is the cheapest insurance available.
• Because Amazon itself no longer accepts it. Every Amazon pipeline that used to take a .mobi has closed, which means the format's original home is now the one place you cannot use it.

MOBI's Place in the Kindle Format Line

Amazon's MOBI Retirement, Step by Step

Frequently Asked Questions

Is MOBI still supported by Kindle?

Not for anything new. Amazon removed MOBI from Kindle Direct Publishing in two stages — reflowable books on 1 August 2021, fixed-layout books on 18 March 2025 — and Send to Kindle stopped accepting .mobi and .azw personal documents during 2022 in favour of EPUB. Books already in your Amazon library are unaffected, and an older Kindle will still read a .mobi copied into its Documents folder over USB. What you can no longer do is email, upload or wirelessly send one to a Kindle. Converting to EPUB restores every one of those routes.

Should I convert MOBI to EPUB or to AZW3?

EPUB, for nearly everyone. Send to Kindle accepts EPUB and converts it on Amazon's side, so it is the officially supported path onto a modern Kindle — and the same file also works on Kobo, Nook, Apple Books, Play Books and every desktop reader, which matters if you ever change devices. AZW3 is Amazon's own container and only makes sense when you are sideloading directly to a pre-KFX Kindle and want a Kindle-native file. This converter targets EPUB, which is the practical answer to "make my old book readable again".

Will converting MOBI to EPUB keep my chapters, table of contents and images?

Structure survives; fine styling is approximate. Both formats store a book as structured HTML-like content with a navigation document, so chapter breaks, the linked table of contents, inline images and core metadata such as title and author map across cleanly. Where you may see drift is layout: MOBI's presentation model predates EPUB 3 by more than a decade and expresses far less, so a heavily designed or illustrated title can shift. Ordinary text-and-image books convert without fuss.

What is the actual difference between MOBI and EPUB?

MOBI is a record-based file inherited from the Palm era, tied to one vendor who has since abandoned it, with no published specification and a limited presentation model. EPUB is a ZIP package of XHTML, CSS, SVG and images described by an open W3C standard — EPUB 3.3 became a Recommendation in May 2023 and is still being revised — with rich layout, embedded media and a fixed-layout profile alongside the reflowable default. The practical difference is support: EPUB opens on essentially every modern reader, while MOBI is increasingly a format you have to convert before you can read it.

Should I convert MOBI to PDF instead?

Only if you need the page frozen. PDF is the right answer for printing, marking up, or handing someone a copy that must look pixel-identical on their machine. It does not reflow, so on a phone or a six-inch e-reader you end up pinching and scrolling through a page laid out for A4 or Letter. For actual reading, MOBI to EPUB is better because the text adapts to the screen and to the font size you chose; use MOBI to PDF when the output is going to paper or to an annotation workflow.

Why did my MOBI file fail to convert?

The overwhelmingly common cause is DRM. Books bought from the Kindle store are wrapped in Amazon's rights management, and a converter that reaches encrypted content stops rather than working around it — that is the intended behaviour, not a bug to route around. The other causes are mundane: a truncated download, a .prc or .azw renamed to .mobi that is not actually a Mobipocket document, or a file that was already a placeholder rather than the book. DRM-free MOBIs — from Project Gutenberg, indie publishers, bundles, or your own production pipeline — convert normally.

What opens a .mobi file on my computer today?

Calibre is the reliable answer on Windows, macOS and Linux, and it will also read the metadata and cover so you can confirm what a file actually is. The Kindle desktop and mobile apps still open MOBI files you sideload, and older Kindle hardware reads them from the Documents folder over USB. What will not open one is a browser, a phone's default reader, Apple Books or Google Play Books — which is exactly why converting to EPUB tends to be simpler than hunting for a reader.

What happens to my book after I convert it?

Your file is uploaded over an encrypted connection, converted on our servers, and both the upload and the converted result are deleted automatically after a few hours. There is no account requirement, no email address, no watermark on the output, and your books are never shared or made public. There is no fixed per-file cap — MOBI ebooks are small, usually well under 50 MB even for illustrated titles — so upload speed is the only practical limit on a large batch.