What is Kindle Unlimited?

Kindle Unlimited (KU) is Amazon's monthly subscription service that lets readers borrow and read as many enrolled eBooks as they like. For self-published authors, the way into KU is enrolling the eBook in KDP Select, which requires the eBook to be exclusive to Amazon.

You are not paid per borrow. Instead, Amazon sets aside a fund each month — the KDP Select Global Fund — and divides it among authors according to how many pages of their books KU readers read for the first time, measured in Kindle Edition Normalized Pages (KENP). The per-page rate therefore changes month to month, and Amazon announces it after the month ends. Check KDP's reports for current figures rather than relying on old numbers.

Because income depends on pages actually read, KU rewards books that readers finish and series that keep readers moving to the next book. Genres with fast, voracious readers tend to do especially well. A KU read does not earn a sales royalty, though it does help your book's visibility on Amazon.

KU is available in many but not all Amazon marketplaces. The trade-off is giving up other eBook stores for as long as the book is enrolled. Some authors put the first books in a series in KU and keep others wide; check KDP's current rules on what exclusivity covers.