KDP takes a Word file as it is, so a Kindle ebook does not need an EPUB. Apple Books, Kobo, Google Play and Barnes & Noble Press take EPUB files and validate them. One EPUB can go to all of them, KDP included.
What the conversion has to get right
Headings become the contents
Every EPUB has to carry a navigation document, which reading apps show as the table of contents. A converter builds it from the headings, so mark chapters with Word's heading styles rather than with bold or larger text.
Pictures need a description
What you type in Word's Alt Text pane is what a screen reader says for the picture. A file name or “Figure 3” describes nothing.
The accessibility metadata has to be true
Since June 2025 the European Accessibility Act asks ebooks sold in the EU to state how accessible they are. Five properties carry that statement, and EPUB accessibility and the EU Act explains each.
The file has to pass EPUBCheck
EPUBCheck is the validator for the format, and Apple Books and Kobo run it on upload. EPUBCheck errors, decoded gives its messages and what causes them.
Page layout does not travel
An ebook reflows to the reader's screen. Page size, page numbers, headers and footers do not carry over, and text boxes and drawn shapes have no place in the flow of text.
Check the result
KDP says most Word files convert well, and that complex formatting may not. It recommends checking a book in Kindle Previewer before you upload. The free EPUB checker reads the accessibility metadata of any EPUB and whether the file backs it up.
What Torcul does
Torcul reads the headings of a Word or Markdown manuscript and shows how each was read before it builds. The EPUB carries a contents list made from those headings, the alt text written in Word, and accessibility metadata written from the book itself.
Text boxes, charts and drawn shapes are left out, and Torcul says how many when it reads the file. The EPUB is checked with EPUBCheck before you download it.
Sources
None of this guarantees that a store will accept a file. Stores change their requirements, so check the date on this page.