EPUB to MOBI Converter turns an EPUB ebook into a MOBI file, the Mobipocket format that every Kindle e-reader understands, including the oldest models that cannot open EPUB at all. Drop in a DRM-free EPUB 2 or EPUB 3 file, click Convert to MOBI and download the result. The converter writes a classic MOBI (KF7) file with the cover set as the Kindle cover, a contents page that links to every chapter and sub-chapter, a page break before each chapter, and the book images. Headings, paragraphs, italics and bold, lists, quotes, tables and links are kept, while CSS styling is simplified because the MOBI format supports very little of it. Pictures in WebP or SVG, which older Kindles cannot show, are converted to JPEG, and very large images are scaled down. The book is marked as an ebook rather than a personal document, so it appears under Books on the device. Before converting, note one change Amazon made in 2022: Send to Kindle no longer accepts MOBI files but does accept EPUB, so if you send books by email or with the Send to Kindle app, send the EPUB directly. MOBI remains the right choice for copying books over USB to older Kindles and for apps that only read MOBI. Everything runs in your browser and the book is never uploaded. To change the title, author or cover first, use EPUB Metadata Editor, and to go the other way use MOBI to EPUB Converter.
For years converting EPUB to MOBI was the standard way to get a book onto a Kindle, because Kindles never supported EPUB directly. That changed in 2022, when Amazon stopped accepting MOBI through Send to Kindle and started accepting EPUB instead, converting it on its servers to the format each device needs. Today the question is therefore how the book will reach the Kindle. If you email it or use the Send to Kindle app or website, send the EPUB, and Amazon takes care of the rest. If you copy books over USB, or own an older Kindle that no longer receives updates, or use an app that only reads MOBI, a MOBI file is still what you need. Older Kindles read the MOBI format natively, and newer ones still open it. Under the hood a MOBI file is a Palm database: a header record with the metadata, the text as one HTML document split into compressed 4096-byte records, then the images, one per record. Links inside the book point to byte positions in the text, so the converter assembles the whole document first, then writes every link position once the targets are known. The cover is registered in the EXTH metadata so the Kindle shows it in the library, and the book type is set to EBOK so the Kindle files it under Books instead of Docs.