EPUB vs PDF for Dyslexia — Why Converting PDFs to EPUB Helps Dyslexic Readers
PDF is a visual format — every page is a fixed image with locked fonts, sizes, and spacing. For dyslexic readers who benefit from larger type, different fonts, wider spacing, or coloured backgrounds, PDF is inaccessible. Converting to EPUB unlocks all these accommodations.
The PDF accessibility problem for dyslexic readers
PDF forces you to read at the author's chosen settings:
- Fixed fonts — usually Times New Roman or Arial at 10-12pt, chosen for print
- Fixed spacing — tight letter-spacing and line-height typical of print journals
- Fixed background — always white; you cannot apply a cream or coloured overlay
- Fixed size — zoom increases the image but doesn't reflow text
None of these can be changed without editing the PDF file itself. For dyslexic readers, this means reading every document on the author's terms, not your own.
What EPUB enables for dyslexic readers
| Accommodation | EPUB | |
|---|---|---|
| Font family (OpenDyslexic, sans-serif) | Fixed | Fully customisable |
| Font size | Zoom only (no reflow) | Adjustable, text reflows |
| Letter spacing | Fixed | Adjustable on Kindle, Kobo, apps |
| Word spacing | Fixed | Adjustable on Kindle, Kobo, apps |
| Line height | Fixed | Adjustable |
| Background colour | Always white | Sepia, cream, dark mode, custom |
| Bold text | Fixed weight | Bold option on Kindle |
| Column width | Fixed (two-column for academic PDFs) | Single column, fills screen width |
Converting a PDF to EPUB
- Go to pdf2epub.toolkit.bot
- Upload your PDF
- Wait ~30 seconds
- Download the EPUB
The converter handles most text-based PDFs well — books, papers, reports, documents. Once you have the EPUB, transfer it to your preferred reading device and apply your dyslexia-friendly settings.
Dyslexia settings on Kindle
Open any EPUB (sent via Send to Kindle) → tap the Aa button → adjust:
- Font: Choose 'Dyslexie' or 'OpenDyslexic' (available on Kindle firmware 5.12+)
- Font size: Use the slider — 14-18pt is often comfortable
- Bold: Enable to increase weight for better letter distinction
- Letter spacing: Increase in the 'Layout' tab
- Line spacing: Increase for more comfortable reading
- Background: Switch to Sepia (warm cream) or Dark mode
Dyslexia settings on Kobo (OpenDyslexic)
Kobo has the best built-in dyslexia font support. Open any EPUB → tap the Aa button:
- Font → OpenDyslexic: Kobo's native OpenDyslexic support — no extra installation
- Font size: Adjust with the slider
- Line spacing, word spacing, letter spacing: All adjustable in the typography panel
- Reading colour: Settings → Accessibility → Reading Colour — apply coloured overlays
Dyslexia settings in reading apps
| App | Platform | OpenDyslexic? | Spacing control? |
|---|---|---|---|
| Apple Books | iOS, Mac | Via iOS system fonts | Limited |
| Google Play Books | Android, iOS, web | No native — use system font | Line spacing yes |
| Lithium / Moon+ Reader | Android | Yes (import font file) | Full control |
| KOReader | Kobo, reMarkable, Android | Yes (import font file) | Excellent — full CSS control |
| Readium / Thorium | Windows, Mac, Linux | Yes | Full EPUB accessibility spec |
Frequently asked questions
Why is EPUB better than PDF for dyslexia?
EPUB is a reflowable format that lets readers control typography: font family, font size, letter spacing, word spacing, line height, and background colour. All of these are evidence-based accommodations for dyslexia. PDF is a fixed-layout format — you cannot change its fonts or spacing without editing the source file. Converting a PDF to EPUB unlocks full typography control on any reading device or app, making the same document significantly more accessible for dyslexic readers.
Which fonts help dyslexic readers?
Research shows several font features help dyslexic readers: (1) OpenDyslexic — specifically designed for dyslexia, available in Kobo and some reading apps; (2) Arial and other sans-serif fonts — cleaner letterforms than serif fonts for most dyslexic readers; (3) Larger font sizes — 14-18pt is often more comfortable than standard 11-12pt; (4) Increased character spacing — reduces letter confusion. Kindle offers limited font choices; Kobo offers OpenDyslexic natively in Settings → Accessibility. Most EPUB reading apps (Apple Books, Google Play Books) support custom fonts.
Does Kindle support dyslexia-friendly reading?
Yes — Kindle has a 'Dyslexie' font option (on Kindle devices with firmware 5.12+) and allows font size adjustment, bold text, letter spacing, word spacing, and line spacing adjustments. These settings work on EPUB files sent to Kindle (via Send to Kindle), but not on PDFs in Kindle's PDF viewer. Converting a PDF to EPUB and sending to Kindle unlocks all these accessibility options.
Does Kobo support OpenDyslexic font?
Yes — Kobo has built-in OpenDyslexic font support. Go to any book → Aa (font settings) → Font → scroll to OpenDyslexic. This is available on all current Kobo models. Combined with Kobo's line spacing, word spacing, and font size controls, Kobo offers excellent dyslexia-friendly customization. But again — these settings only work on EPUB files, not on PDFs read in Kobo's PDF viewer. Converting PDFs to EPUB first is essential.
What background colour helps dyslexic readers?
Many dyslexic readers find high-contrast black-on-white text causes 'visual stress' — text appears to shimmer or move. Softer backgrounds help: cream/sepia backgrounds (built into Kindle as 'Sepia' mode and Kobo as 'Warm' reading colour), light yellow, or light blue. Some readers prefer dark mode (light text on dark background). EPUB files let you set background colour in the reading app. PDFs have fixed colours — you can't change the background without editing the file.