Cracking the Amazon Ranking Code

Note – This is a completely fun and unscientific analysis of Amazon 🙂

Every author will tell you they don’t look at their Amazon ranking for a number of reasons like:

–Ranking only takes into account the books (print or digital) sold on Amazon, and not in book stores or on Google Books or iBooks or the like;


–Because there are about 6 million books on Amazon the coding that determines the ranking takes into consideration tons of little things that don’t determine your book’s sales, but only how your book compares to others sold on Amazon;


–There is no definitive number of books sold that equates a certain overall ranking number


–Because your agent, publisher and other authors all tell you not to pay attention to Amazon rankings because their agent, publisher or other authors told them that too.

Yet, every single person with a book or product on Amazon checks their Amazon ranking. It’s just a fact. Even as authors’ check their ranking they actively tell other authors or people not to check it for any one of the aforementioned four reasons. As William Wallace from Braveheart said


There it is. I’m now free… I check my Amazon ranking! Sometimes once a week; sometimes once every other day; sometimes twice a day. I don’t know. There’s no rhyme or reason. Some of it is just the shear shock that people still want to read my book 🙂

Anyway, the other week I noticed that on my book’s page it said there were

“18 books left in stock — more to come soon”

It was 3pm on a Tuesday afternoon and my overall Amazon ranking was 21,648 out of the 6,000,000-something books on Amazon. I figured that would be a fun barometer to see how long it took to sell those 18 books.

Wednesday afternoon at 3pm it said there were 14 books left in stock, and my ranking was 17,237. 4 books sold in one day made my book jump about 4,000.

Thursday afternoon at 3pm it said there were 7 books left in stock, and my ranking was 12,894. 7 books sold in one day made my book jump about 5,000.

Friday afternoon at 3pm it said there was 1 book left in stock, and my ranking was 10,945. 6 books sold in one day only made my book jump about 2,000.

Saturday afternoon at 3pm my book was fully restocked and the ranking was back up to 18,545… and I was back to not knowing anything. Here’s what I concluded from my happen-chance three day experiment:

I definitively sold 17 print books in a 72 hour period (average of 5.7 books sold per day), and that lowered my overall Amazon ranking by about 11,000. Now once again, that ranking is dependent upon how all of the other 6,000,000 books sell, but at least I can deduct this:

By that equation (which I can guarantee you is not accurate to Amazon’s actual coding) every book sold lowers the ranking by about 647 positions in Amazon’s overall ranking based on about 5.7 books sold per day, which, by my ranking in Year 2 of my book’s existence, is a pretty consistent fluctuation of the overall rankings of where my book sits (usually between 10,000-28,000 overall ranking).

Thus, my guess–in my book’s current pace–is that if my overall ranking is around 10,000-12,000, I’ve probably sold about 15-17 books in the previous three days; or about 5 or 6 books per day. If my overall ranking is around 20,000-28,000, I’ve probably sold about 8 books, or 2.5 books per day. If it’s around 50,000 it’s about 1 book per day; 100,000 1 book every other day; and so on.

So go on, continue checking those Amazon rankings and one day you too will know how many books you sell-ish. Kind of. Well, not really. We’ll never know the code. I just thought this was fun and like my deductions – even if they’re totally wrong 🙂

Much love.

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  • Hang on, no-one told me I shouldn’t be checking my Amazon ranking, I’ve been checking it every day! How did I miss such important advice? And given that I do check, why didn’t I get stuck in with the maths as you have?!

  • Not bad, Andrew. I think you are as close as one can get to understanding Amazon’s algorithm rankings.

  • Hang on.. don’t you know how many books you *have* sold from what I would imagine is your royalties report?