How do footnotes work in EPUB 3?

EPUB 3 supports popup footnotes using epub:type='noteref' on the reference link and epub:type='footnote' on the note content (an aside element). Reading systems that support this — Apple Books, Thorium Reader, Kindle apps — display the note as an inline popup without navigating away from the text.

What is epub:type='noteref'?

noteref is an epub:type semantic applied to the anchor tag that links to a footnote. It marks the superscript number or symbol as a note reference. Combined with epub:type='footnote' on the note target, it enables popup note behavior in supporting reading systems.

Should I put footnotes in the same file or a separate file?

For a few footnotes per chapter, putting them in the same XHTML file (as aside elements after the main content) is simpler. For books with many notes (academic works, annotated texts), a separate notes.xhtml file is cleaner. Include the notes file in the OPF spine with linear='no' so it doesn't appear as a chapter.

What is the difference between epub:type footnote and endnote?

Both are note container types. footnote is traditionally bottom-of-page (though in EPUB both display as popups in supporting readers). endnote is for notes collected at the end of a chapter or book. Use footnote for popup-style notes and endnote when notes appear in a separate section at the back.

How do I make EPUB footnotes accessible to screen readers?

Add DPUB-ARIA roles alongside epub:type: role='doc-noteref' on the reference link and role='doc-footnote' on the note aside. Add aria-label='Footnote N' to both elements. Screen readers use these roles to announce note references and enable quick navigation between all notes in the document.

EPUB Footnotes and Endnotes: Popup Notes, Asides, and Best Practices

June 12, 2026 · 7 min read

Footnotes in e-books work differently from print. Good EPUB footnotes use popup notes that appear inline without navigating away from the text — a much better reading experience. Here's how to implement footnotes correctly for EPUB 3.

Three Footnote Approaches

Approach	EPUB version	Reader support	Reading experience
Linked footnotes (same file)	EPUB 2 + 3	Universal	Navigates to note, back button returns
Linked footnotes (separate file)	EPUB 2 + 3	Universal	Navigates to notes chapter
Popup notes (epub:type="footnote")	EPUB 3 only	Modern readers	Inline popup, no navigation

EPUB 3 Popup Footnotes (Recommended)

EPUB 3 popup notes use epub:type="noteref" on the reference and epub:type="footnote" or epub:type="endnote" on the note content. Supporting readers (Apple Books, Thorium Reader, Kindle for iOS/Android) display these as popups.

<!-- In the chapter text -->
<p>
  The author argues this point at length.<a
    epub:type="noteref"
    href="#fn1"
    id="fn1-ref"
    role="doc-noteref"><sup>1</sup></a>
</p>

<!-- Note definition — can be in same file or a separate notes file -->
<aside
  epub:type="footnote"
  id="fn1"
  role="doc-footnote">
  <p><sup>1</sup> Smith, J. (2024). <em>The Complete Argument</em>, p. 42.</p>
</aside>

Footnotes in a Separate File

For books with many notes, keeping them in a separate notes.xhtml file is cleaner:

<!-- In chapter01.xhtml -->
<a epub:type="noteref" href="../notes.xhtml#fn1" role="doc-noteref"><sup>1</sup></a>

<!-- In notes.xhtml -->
<aside epub:type="footnote" id="fn1" role="doc-footnote">
  <p><sup>1</sup> Full citation here.</p>
</aside>

Include the notes file in the OPF spine with linear="no" so it doesn't appear as a chapter:

<itemref idref="notes" linear="no"/>

Endnotes vs Footnotes

In EPUB terminology:

epub:type="footnote" — appears at bottom of page (print concept; in EPUB displayed as popup)
epub:type="endnote" — appears at end of chapter or book
epub:type="rearnote" — appears at end of book (alternative to endnote)

In practice, use footnote for popup-style notes and endnote when notes are collected at the back. The popup behavior depends on the reading system, not just the epub:type value.

Accessibility for Notes

Use ARIA roles alongside epub:type for maximum accessibility:

<a epub:type="noteref" href="#fn1" role="doc-noteref"
   aria-label="Footnote 1"><sup>1</sup></a>

<aside epub:type="footnote" id="fn1" role="doc-footnote"
       aria-label="Footnote 1">
  <p>Note content here.</p>
</aside>

Screen readers use role="doc-noteref" and role="doc-footnote" (from the DPUB-ARIA vocabulary) to announce note references and allow quick navigation between notes.

Footnotes from PDF Conversion

PDFs with footnotes store the note text at the bottom of the page. When converting with toolkit.bot, footnote text is detected and linked back to the reference point using EPUB 3 popup note markup. The reading flow stays intact — notes don't interrupt the main text.

Convert PDF with footnotes to EPUB →