EPUB is the closest thing ebooks have to a universal standard. Almost every store and library uses it — except Amazon, which uses its own formats. Here’s how to get EPUBs onto every e-reader brand.
The EPUB Compatibility Table
| Brand | Native EPUB Support | Method |
|---|---|---|
| Kobo | ✅ Yes | USB copy or Calibre |
| Boox | ✅ Yes | USB, cloud, apps |
| PocketBook | ✅ Yes | USB, Dropbox, microSD |
| reMarkable | ⚠️ Converted | USB or app (converted internally) |
| Kindle | ❌ No | Send to Kindle (auto-convert) or Calibre |
Kindle: EPUB Needs Conversion
Kindle does not read EPUB directly. You have two options:
Option 1: Send to Kindle (easiest)
Amazon’s “Send to Kindle” service accepts EPUB files and converts them automatically behind the scenes. Use the Send to Kindle web page, the desktop app, or email. The converted book appears in a Kindle library across all devices, complete with Whispersync. This is the simplest method for most users.
Option 2: Calibre conversion (more control)
Convert EPUB to AZW3 in Calibre: Add book → Convert books → choose AZW3 output → transfer via USB. This gives you more control over formatting and metadata, avoids Amazon’s cloud, and works entirely offline. Use this if you want to keep a library independent of Amazon’s ecosystem.
Kobo: Plug and Play
Kobo supports EPUB natively. Connect via USB, drag EPUB files to the Kobo drive, eject. That’s it. Covers, metadata, and formatting render correctly without any conversion.
For optimal results, convert to KEPUB (Kobo’s enhanced EPUB format) using Kepubify. KEPUB enables reading stats, faster page turns, and better image zoom. Calibre with the Kobo Utilities plugin can auto-convert during transfer.
Boox: Android Means Everything
Boox runs Android, so EPUB support depends on which app you use. NeoReader (built-in) handles EPUB well. You can also install KOReader, Moon+ Reader, or any Android reading app from Google Play. Transfer via USB, Dropbox, or Google Drive.
PocketBook: Broadest Format Support
PocketBook supports 20+ formats natively. Copy EPUBs via USB—they appear immediately. You can also use Dropbox (built-in) or a microSD card.
reMarkable: EPUB with a Caveat
reMarkable accepts EPUBs but converts them internally to its own format. The conversion is lossy — complex formatting, embedded fonts, and tables may not survive. For best results, convert to PDF before sending to reMarkable.
Universal Sideloading with Calibre
Calibre handles device detection and auto-conversion. Plug in an e-reader, drag books to the device icon, and Calibre converts to the correct format on the fly. See our sideloading guide for brand-by-brand details.
Why Not Just Use MOBI?
Until late 2022, MOBI was the standard format for Kindle sideloading. Amazon has since deprecated it — Send to Kindle no longer accepts MOBI files, and newer Kindle features (custom fonts, enhanced typesetting, page flip) are unavailable in MOBI format. Any MOBI files in your library should be converted to EPUB or AZW3.
AZW3 (KF8) is the modern Kindle format. It supports embedded fonts, advanced layout, and better image rendering than MOBI. Use it for USB sideloading to Kindle. Use EPUB with Send to Kindle for wireless delivery.
Common Problems When Converting EPUB to Kindle
Tables and complex layouts break. Amazon’s conversion engine simplifies CSS aggressively. Multi-column tables, code blocks, and fixed-layout elements often collapse. If formatting matters, convert to AZW3 in Calibre and sideload via USB — this preserves formatting that Send to Kindle would destroy.
Fonts do not carry over. Embedded fonts in EPUBs are stripped during Amazon’s cloud conversion. The default Kindle font replaces them. For custom fonts, sideload via USB in AZW3 format with the font properly embedded, or install the font file directly on the Kindle.
Book is too large for Send to Kindle. The 50 MB limit applies to all Send to Kindle methods — web, email, app. Large illustrated books, manga, and image-heavy EPUBs frequently exceed this. USB sideloading has no size limit.
Frequently Asked Questions
Can I convert EPUB to Kindle format without losing formatting?
Yes, using Calibre’s AZW3 conversion. In Calibre: right-click the book → Convert books → Convert individually → set Output format to AZW3 → under “Look & Feel,” check “Embed all fonts” → convert. Transfer the resulting AZW3 file via USB. This preserves embedded fonts and advanced CSS far better than Amazon’s server-side EPUB conversion.
Why do some EPUBs look fine after Send to Kindle but others do not?
EPUBs from standard sources (Kobo store, Standard Ebooks, Project Gutenberg) usually convert cleanly because they use simple, standards-compliant markup. EPUBs with heavy CSS, custom JavaScript, fixed layouts, or publisher-specific styling (from Google Play Books, Apple Books) often break because Amazon strips anything not in its supported subset. When in doubt, preview on the Kindle immediately and have a USB cable ready for fallback.
Can I read library EPUBs (OverDrive/Libby) on a Kindle?
Only in the US. Libby sends library books to Kindle through Amazon’s website, not as raw EPUB files. The Kindle never sees the EPUB — Amazon converts it server-side and delivers a Kindle-formatted version. Outside the US, library EPUBs cannot be read on a Kindle at all. Use a Kobo or PocketBook with built-in OverDrive support for international library access.
Is EPUB better than PDF for e-readers?
For reflowable text — novels, nonfiction, articles — EPUB is vastly better. Text reflows to fit any screen size, fonts are adjustable, and reading progress syncs across devices. PDFs are fixed-layout: the page never changes, making them ideal for textbooks and documents with diagrams but painful on small screens where you must zoom and pan constantly. For a full comparison, see EPUB vs MOBI vs PDF.