The numbers
| Format | What it is | KDP notes |
|---|---|---|
| EPUB | open standard, reflowable or fixed layout | accepted; check it in Kindle Previewer before uploading |
| DOC / DOCX | Word document | recommended; complex formatting may convert less well |
| KPF | Kindle Package Format, made with Kindle Create | recommended |
| print-style document | accepted in a limited set of languages | |
| HTML (ZIP, HTM, HTML), RTF, TXT | text and web formats | accepted |
| MOBI | older Kindle format | no longer accepted |
Reflowable and fixed-layout EPUB
The same format covers both kinds of eBook. A reflowable EPUB lets the text adapt to the screen and the reader's settings: right for novels and most non-fiction. A fixed-layout EPUB declares its pages as pre-paginated, so every page keeps its design: right for picture books and comics.
File size costs money on the 70% option
On the 70% royalty option, KDP subtracts a delivery cost based on the converted file size: $0.15 per MB on Amazon.com, with sizes rounded up to the kilobyte. Uncompressed images in an EPUB make every sale cost more.
Example: the same $4.99 price, two file sizes
A 2 MB novel at $4.99 on Amazon.com earns $3.28 at 70% (after a $0.30 delivery cost) or $1.75 at 35%.
A 25 MB picture book at the same price earns only $0.87 at 70%, because delivery costs $3.75, so the 35% option ($1.75) pays more.
Common mistakes
- Uploading a MOBI file.
- Skipping Kindle Previewer: layout problems show up after publishing instead of before.
- Embedding full-resolution print images, which inflates the file and the delivery cost.
- Uploading the print PDF as the eBook: the result reads like a scanned book on a phone.
- Putting text inside images in a reflowable book, where readers can't resize it.
In kdpbook: kdpbook exports a Kindle EPUB, reflowable or fixed layout, along with a separate Kindle cover.