Every book on this site is offered in three formats. They contain the same text, the same chapter breaks and the same notes — what differs is which device opens them without conversion.
The short answer
| Format | Made for | Also works on |
|---|---|---|
| EPUB | Apple Books, Google Play Books, most apps | Kobo, Nook, Onyx Boox, desktop readers |
| AZW3 | Kindle e-readers and the Kindle app | Calibre can convert it to anything |
| KEPUB | Kobo devices | Nothing else — it is a Kobo extension |
What actually changes
EPUB is a zip of XHTML files with a package document. It reflows, respects the reader’s font and margin settings, and is the format the publishing industry settled on.
AZW3 (also called KF8) is Amazon’s successor to MOBI. It supports embedded fonts and better typography than MOBI, and is what you want if you are copying a file straight onto a Kindle by USB.
KEPUB is EPUB with Kobo’s proprietary spans added. Those spans are what give Kobo its page-count and reading-time display; a plain EPUB on a Kobo will show approximate pages instead.
Practical advice
- Kindle Paperwhite, Oasis, Scribe, or the Kindle app: take AZW3.
- Kobo Clara, Libra, Sage: take KEPUB if you care about page numbers; otherwise EPUB is fine.
- iPad, Android tablet, phone, desktop: take EPUB.
- Not sure: take EPUB. It is the format everything can convert from.
Related
Frequently asked questions
What is the difference between EPUB and AZW3?
EPUB is the open standard read by Apple Books, Kobo, Google Play Books and most apps; AZW3 is Amazon’s Kindle format. The words are the same; the container differs.
What is KEPUB?
Kobo’s variant of EPUB. It adds page numbers, reading statistics and faster page turns on Kobo devices, which plain EPUB does not support.
Can a Kindle read EPUB?
Newer Kindle models accept EPUB through Send to Kindle, which converts it. For a direct USB copy, AZW3 is the safer choice.
Can Kobo read AZW3?
No. Kobo reads EPUB and KEPUB only.
Is one format better quality than another?
No. All three here come from the same source text; only the packaging differs.
Which should I download for a tablet or phone?
EPUB — it works in Apple Books, Google Play Books, Moon+ Reader and most other apps.