Amazon is introducing a new system that completely upends the way authors and publishers make money from their books. Starting next month, the company will pay authors based on the number of pages people read from their books — not the number of copies sold.

Of course, the change is limited in scope — at least for now. The new system adjusts how authors receive royalties for books listed on the Amazon Lending Library (included for free for every Prime customer) or Kindle Unlimited, both of which use a subscription model. Specifically, the rules apply to authors enrolled in Amazon's Kindle Direct Publishing (KDP) Select program, which provides an easy outlet for authors to self-publish their books. It's not clear how or if the new system will apply to books from major publishers that are included in the Lending Library catalog.

Both the Lending Library and Kindle Unlimited divide a monthly pool of cash ($10.8 million last month) to KDP Select authors. The difference now is that the money will be parsed out based on how many pages people actually read of an author's book, not how many times it is downloaded or "borrowed." So, whereas each qualifying download used to increase an author's share of the pie, now total page turns per month will be used to determine how much each author gets from the monthly fund.

Introducing KENPC 1.0, a metric for measuring page turns

Perhaps most interesting of all is the wonderfully geeky "Kindle Edition Normalized Page Count" (KENPC v1.0). This new metric defines what a "page" really is. According to Amazon, "We calculate KENPC based on standard settings (e.g. font, line height, line spacing, etc.), and we'll use KENPC to measure the number of pages customers read in your book." So that means authors can't game the system with grade school tricks like reducing the margins or bumping up the font size. Notably, images, graphs, and graphics will count towards the official page tally. Readers will also have to linger on a page long enough to read it before it'll count for a royalty check.

Amazon says that the change comes in response to some complaints from authors of longer books, who felt short-shrifted under the old system. As the company says in its announcement, authors consistently said "that paying the same for all books regardless of length may not provide a strong enough alignment between the interests of authors and readers. We agree."

Instead of simply paying more royalties for longer books, however, Amazon tried something very different. A representative tells The Atlantic that "We think this is a solid step forward," adding, "our goal, as always, is to build a service that rewards authors for their valuable work, attracts more readers, and encourages them to read more and more often."

Correction: The original version of this article conflated Kindle Direct Publishing (KDP) and KDP Select. The new royalty system only applies to KDP Select authors, who have their books offered on both the Lending Library and Kindle Unlimited as part of the program. In addition, the $3 million pool number originally quoted is merely the base fund — Amazon's total fund was $10.8 million in May. We regret the error.