Formats
What converts to what
The complete capability list, including the things this build refuses to do and why. Everything marked here as working is covered by tests that convert a real file and read the result back.
The conversion matrix
| From ↓ / To → | EPUB | MOBI | CBZ | |
|---|---|---|---|---|
| EPUB | Yes | Yes | Image books only | Image books only |
| MOBI | Yes | Yes | — | — |
| AZW3 | Yes | Yes | — | — |
| Experimental | — | — | — | |
| CBZ | Yes | Yes | Yes | Yes |
| Images | Yes | — | Yes | Yes |
“Image books only” means the source has to be pages of pictures — a comic archive, a folder of scans. Turning a book of text into pictures would lose selectable text, adjustable type and the contents list.
Every format
| Format | Read | Write | Reflows | What it is |
|---|---|---|---|---|
| EPUB .epub | Yes | Yes | Yes | The open standard. Reflows to any screen, and read by everything except Kindle hardware. |
| Mobipocket (MOBI) .mobi .prc .azw | Yes | Yes | Yes | The older Kindle format. Simple, universally accepted by Kindle software, limited styling. |
| Kindle Format 8 (AZW3) .azw3 .kf8 | Yes | No | Yes | The newer Kindle format. Proper CSS and typography, built on the same structure as EPUB. |
| PDF | Yes, via PDF.js | Image books only | No | Fixed pages. Looks identical everywhere and cannot reflow to a small screen. |
| Comic Book ZIP (CBZ) .cbz | Yes | Image books only | No | A ZIP of page images in reading order. The standard way comics are stored. |
| Comic Book RAR (CBR) .cbr | No | No | No | The same idea as CBZ but compressed with RAR, which browsers cannot unpack. |
| Page images (PNG, JPEG, WebP, GIF) .png .jpg .jpeg .webp .gif | Yes | No | No | Scanned or exported pages, assembled into a book in filename order. |
Recognised, and deliberately refused
These are identified on sight. A file this site knows the name of deserves better than “unsupported file”.
CBR (RAR comic archive)
CBR files are compressed with RAR, which is proprietary and has no permissively licensed decoder small enough to send to a browser. Almost every comic reader can re-save a CBR as a CBZ, and a CBZ converts here without any loss — the images inside are identical.
RAR archive
RAR is proprietary and cannot be unpacked in a browser. If this is a comic, re-save it as a CBZ; if it is a general archive, unpack it first and add the files inside.
DRM-protected book
This book is encrypted with digital rights management. Book Batcher does not remove DRM and will not try to. Books bought from a store that applies DRM can usually be downloaded again in an open format from the publisher, or borrowed through a library app that handles the decryption itself.
Word document
A Word document is a layout format with its own styling model. Converting one to an ebook well means interpreting styles, numbering and section breaks. Word can export EPUB or PDF directly, and either of those converts here.
FictionBook (FB2)
FB2 is a single XML file with its own schema for structure and footnotes. It is a genuinely convertible format and simply is not implemented here yet.
AZW3 as an output
AZW3 output is not offered. Writing Kindle Format 8 correctly means building the skeleton, fragment and index records a Kindle uses to paginate, and a file that opens but paginates wrongly is worse than one that was never offered. MOBI is written instead: every piece of Kindle software reads it, including current devices and Send to Kindle.
Pages for each conversion
- EPUB to MOBI converterConvert EPUB books to MOBI for Kindle, in your browser. Keeps the cover, the metadata and a working table of contents. No upload, no account, no queue.
- MOBI to EPUB converterConvert MOBI books to EPUB in your browser. Rebuilds the chapters, keeps the images and the cover, and writes navigation that older readers understand too.
- AZW3 to EPUB converterConvert Kindle AZW3 books to EPUB in your browser. Reads the Kindle Format 8 document structure, so the original chapter divisions survive.
- PNG and JPG to EPUB converterTurn a folder of page images into one EPUB. Pages are ordered by filename with a natural sort, so page 10 follows page 9. Works with PNG, JPEG, WebP and GIF.
- CBZ to EPUB converterConvert comic archives to EPUB in your browser, with the pages in the right order and the metadata from ComicInfo.xml carried across.
- CBZ and image folder to PDFTurn a comic archive or a folder of scans into a PDF, one page per image. JPEG pages are copied without re-encoding, so nothing is lost.
- PDF to EPUB (experimental)Reflow a PDF into an EPUB in your browser. A PDF stores placed glyphs rather than paragraphs, so the structure is inferred and the result is shown before you download it.
On DRM
Digital rights management is detected — in an EPUB from META-INF/encryption.xml, in a Kindle file from the encryption field in its header, in a PDF from its encryption dictionary — and the file is refused with an explanation. Nothing here removes protection, and nothing here will be added to. Font obfuscation, which is a standard EPUB feature and not DRM, is recognised as such and does not stop a conversion.