How to Make EPUB Accessible for Dyslexia on Kindle & Kobo

What is EPUB and why does it matter for accessibility?

EPUB (Electronic Publication) is the standard open format for e-books. Unlike PDF, EPUB is a reflowable format — the text reflows to fit any screen size or font size setting. This makes EPUB inherently more accessible than PDF, since readers can already adjust font size, line spacing, and margins on their device.

However, the font options built into Kindle, Kobo, and other e-readers are limited. Kindle typically offers Bookerly, Georgia, Palatino, and a few others — none of which are specifically designed for dyslexia. Kobo offers slightly more options but still lacks OpenDyslexic or Lexend by default.

The solution is to embed the dyslexia font directly into the EPUB file. When a font is embedded in an EPUB with proper CSS overrides, it will display that font regardless of what the device offers — essentially overriding the device’s default font selection for that book.

How DysFont converts EPUB files

DysFont’s EPUB font converter works differently from PDF conversion. Since EPUB files are already structured text (they’re essentially zipped HTML/CSS files), no text extraction is needed. Instead, DysFont:

1. Unpacks the EPUB container
2. Embeds the chosen dyslexia font as a font resource within the EPUB
3. Updates the CSS stylesheets to apply the font to all text elements
4. Adds CSS rules to override device font settings (using !important declarations where needed)
5. Repacks the EPUB and returns the converted file

The result is an EPUB that displays your chosen dyslexia-friendly font on any e-reader, regardless of built-in font options.

Step-by-step: convert your EPUB to a dyslexia font

1. Upload your EPUB file

   Go to DysFont and upload your EPUB. The file stays under 10MB for most books. Both EPUB 2 and EPUB 3 formats are supported.

2. Select your dyslexia font

   Choose from OpenDyslexic, Lexend, Atkinson Hyperlegible, Luciole, or 16 other options. Preview how your book will look before committing.

3. Download the converted EPUB

   Download your converted EPUB and transfer it to your e-reader via USB, email, or your device’s send-to-device service.

4. Open on your Kindle, Kobo, or other e-reader

   The embedded font will display automatically. On some devices, you may need to select “publisher font” in the font settings to use the embedded font instead of the device default.

E-reader compatibility guide

Not all e-readers handle embedded fonts the same way. Here’s what to expect:

Which dyslexia font works best on e-readers?

E-reader screens have specific characteristics that affect font rendering:

• E-ink displays (Kindle, Kobo) refresh slowly and render at lower resolution than LCD screens. Fonts with clean, bold strokes tend to render better than thin or delicate fonts.
• OpenDyslexic renders very well on e-ink due to its heavy, rounded strokes. The bold bottom-weighting is clear even at small sizes.
• Lexend is excellent on e-ink for its clean geometry, but thinner weights may appear too light on older e-ink screens. Use Lexend Deca (wider spacing) or a medium weight for best results.
• Atkinson Hyperlegible performs well on both LCD and e-ink, with clear strokes at all sizes.

Tips for the best dyslexia reading experience on e-readers

Once you’ve loaded your converted EPUB, optimize your device settings:

• Set font size to at least 16pt (larger is fine — the reflowable format handles it gracefully)
• Increase line spacing to “Extra” or the maximum setting
• Set the screen to warm light mode (amber) rather than blue-white
• On Kobo: use the “Full justification off” setting for left-aligned text
• Increase brightness slightly — dim screens require more visual effort

EPUB vs PDF: which is better for dyslexic readers?

EPUB is generally preferable to PDF for dyslexic readers. The reflowable text means you can adjust font size without losing content, and line spacing is adjustable. PDF is fixed-layout, meaning the font, size, and spacing are locked unless you use a tool like DysFont to convert it.

If you have a choice of format when downloading educational materials or e-books, always choose EPUB over PDF. If you only have PDFs, DysFont can convert those too. See our PDF to dyslexia format guide for more information.

Color overlays for e-readers: accessibility beyond font choice

Font embedding is just the start. DysFont now supports embedded color overlays in EPUB files — background colors that reduce visual stress and improve focus for readers with Irlen syndrome or ADHD. These are applied via CSS and embedded into the EPUB itself, so they travel with the book to any e-reader.

Approximately 15–25% of dyslexic readers experience visual stress (Irlen syndrome), where pure white backgrounds cause text to shimmer or appear to move. Color overlays are the evidence-based solution:

How overlays work on e-readers

The overlay is implemented as a CSS background-color on the body element of each EPUB chapter. Because it’s embedded in the EPUB itself, it works on:

• Kobo: Full support; displays embedded background color correctly
• Kindle Paperwhite (2021+): Supported when “Publisher font” is selected
• Apple Books: Full CSS support; overlays display automatically
• Calibre and most desktop readers: Full support

Note: Some e-readers allow users to override background colors with their device’s native theme. If the overlay isn’t showing, ensure “Publisher font / Publisher style” is selected in your device reading settings.

Frequently asked questions