Tuesday, September 6, 2011

Amazon Kindle Bestsellers Rank and daily sales

I don’t claim to know how Amazon determines the Bestsellers Rank of my books. Common theories include some algorithm that includes total number of books sold, number of books sold in the past X days, number of books sold in the past y hours, sales of other books, tag activity, page view activity, movement of the asteroid Ceres in relation to the constellation Orion, and so on. Apparently, Amazon also changes their algorithm from time to time. So, if you’re selling 20 books a day and getting into the #4000 range one season, you might sell the same amount next season but barely break #8000.

However, I do keep pretty meticulous sales data for my books and I can try to correlate the number of units I sell to the Amazon Kindle Bestsellers Rank.

Here’s a chart of my best-selling book, Dead Dwarves Don’t Dance. The top graph shows daily unit sales, and the bottom graph shows sales rank.

As you can see, there’s a pretty direct correlation between my spike in sales and my better sales rank. One day in April I sold 126 copies of the book and achieved my best sales rank of #333.

These days, I’m selling between 10 and 20 copies a day, and my sales rank fluctuates around #5000 to #9000.

You can see that around the beginning of March I was also selling around 15 copies a day, and my rank was around #5000.

Even at the current #8000 rank, Dead Dwarves Don’t Dance is showing up in the top #100 for a couple genre lists (Kindle SF High Tech and SF High Tech). Unfortunately, not in the top #20, which is the sweet spot to be in because your book shows up on the first page of the list.

I hope this helps you other writers get a feel for the relationship between daily sales and Amazon Bestsellers Rank.


  1. Thanks, Derek. Appreciate the data you are sharing with us.
    I'm curious as to what effect the lists have. For my case, I don't look at sales rank at all, but OTOH, I don't usually browse. When I do, I'm more likely to look at other customer reviews than sales rank.
    Do you know if sales rank drives the "bought with" or "recommended to go with" lists that come up when looking at a product?

    Again, thanks for sharing.

  2. Hmmm, I'm also constantly baffled by Amazon's rankings. From my own (less than two weeks) experience, just ONE sale can drive the rankings up as much as 100,000 notches! And if you add another sale in the same day, you get up to 20,000 something.

    I can only hope to have sales like yours one day.


  3. Derek - Clearly, there are other factors than individual ebook sales driving the rankings. Given the competitive nature of sales, it stands to reason that the sales of any individual ebook are being compared RELATIVE to sales of others. So, it maybe that on any given day, even if sales of DDDD rise, that increase is compared to the relative changes (increases) in other ebooks.

    My monthly sales have been steadily increasing since last November. I launched Lie Merchants and sold 5 copies in the first month. Changing pricing, product description, social media and time conspired to help lift sales. Now, I am selling about five copies per day and have already exceeded that rate as I write this. Despite that increase, I still have yet to break into the top 10,000 best sellers.

    I hope this isn't true, but I suspect that Amazon.com is not immune to the profit motive. At what point will authors have to pay a "slotting fee" just to get their ebook on the digital "shelf." The day indie authors have to pay $500 to get a "premium" listing in the Kindle Store, the entire industry will suffer. Of course, that opens-up niches for Smashwords and others, but my concern is that they might be doing this now with the big NY houses without anyone knowing about it. Well, that is the free market, right?

    Best of luck and keep up the good posts!

    Cheers - James

  4. J. Viser,

    Erm....not sure if you noticed or not, but Amazon is a business. Businesses exist to make profit for their owners. Therefore, Amazon is ALL ABOUT the profit motive. Otherwise, what's the point? You're out for a profit as well, are you not? There's nothing wrong with the profit motive. It's honest. A hell of a lot more honest than most other motives that people claim to have in public life (of course, when it comes down to it, though, most if not all of those other motives are really BS moralizing designed to disguise some people's desire to make a profit).

    With that in mind, your worries are, I think, unfounded. I've heard this sort of concern voiced all over the place. Let's think this through for a second. They make a TON of money from LOTS of writers and other sellers selling a few things every now and then. The more things up for sale on their store, the more profit they make. Especially in the case of ebooks, it's essentially a free revenue stream, since the cost of storage for an ebook is so close to zero that it's not worth computing, and with basically zero risk for them. So really, think about it from an honest, pragmatic standpoint. Why would Amazon bother limiting the number of products in their store? Sure, they can, and probably should, and probably would (or are), charge advertising fees for more prominent placing. So what? How is that different from any other retail advertising scheme? If/when they do such a thing, it won't be because of a conspiracy, or some nefarious plot. It won't be because the NY publishers feel so threatened by inidies or anything (shoot, in all likelihood they couldn't care less what indie writers do. Indie book sales are a tiny drop in the bucket of the publishing world). It'll be because both parties to the deal perceive a benefit to doing it. And it won't crush indie publishing. Maybe it might make it marginally more difficult to get discovered as an indie. But hell, it's already difficult, no matter what publishing route you take.

    Yes, that is the free market (as much as we allow it to be free anymore, fools that we are). And it's a great thing. Free enterprise is responsible for improving our lives beyond the wildest imaginations of our great-grandparents. Before you knock it, look at the actual results of societies that stifle the free market in favor of some delusion of grandeur or other: they universally result in poverty, ignorance, and misery for all except for a tiny few elites. Yeah, I really want to live there.


    Thanks again for sharing your thoughts and experience.

    Michael Kingswood

  5. Derek -

    To give you another data point, I sell 5-10 copies a day of one of my books, and it ranges between 8000 and 15000 ranking.

    Another of my books sells a bit under one a day, and after each sale, it jumps to the top 50,000, then gradually slides down to about 100,000 in a day, further if it's longer than a day, popping back up when it gets each sale.

  6. Michael Kingswood - Good points all, and I what is ironic is that I usually find myself taking your position in a debate! I don't believe there is anything wrong with Amazon acting like the business it is, it just would be a shame if small authors had to pay a big slotting fee to secure shelf space. I've spent my entire career in business, so I appreciate the profit model.

    That said, I am writing the sequel to LIE MERCHANTS. My earlier comments were most likely the product of the paranoid mindset I develop when writing thrillers, action-adventure novels!

  7. Have my baby Michael Kingswood? haha. Good discussion though. As was said, the worst possible scenario here still has authors in a better position than they have ever been.

  8. Thanks for all the info and comments! It's very difficult to make anything other than general estimates on expectes rank by sales. With a million ebooks in the system, I do find it interesting that it only takes a sale every day or so to get into the top 10%. Apparently, there are a LOT of books that sell very low numbers.

    Michael Kingswood, excellent comments about profit. I would say that I am much more than not immune to the profit motive. I'd say I'm addicted to it. ;)

  9. J. Viser,

    Ok then. Guess I misunderstood where you were coming from. I stand corrected. :)

  10. I know I'm late to this particular party, but listing ebooks, indie or otherwise, isn't quite a "free revenue stream" for Amazon. If I have a query I send an email to Customer Services - and it is answered within hours. If you lived in the UK you would realise this is *spectacular* customer service. It also means that there isn't one guy manning the desk. Add in everyone else, from the programmers to the techies who man the kdp forums, and the backroom staff must be enormous. These people need pay & benefits.

    As to add to the rankings info, my bestseller (I use the term loosely LOL) is selling 2.5 per day and it is currently #31,500.

    Thanks for the info & regular posts, Derek. They are always most informative.

  11. I'm sure that if you tried plotting out the sales/rank ratio on a logarithmic scale, it would make more sense. My theory is that the algorithm for sales rank is a weighted for number of sales and the age of those sales. So a sale today is worth 1 point and a sale from a week ago is worth 0.3 points, and if you're book is about a 6 year old going to heaven a sale is worth 8 points... :)

  12. Good stuff. Kinda looks like fuzzy math, though. As far as the slotting fee, I don't something like that happening soon. But down the road, who knows. Amazon has quietly gotten into the publishing business, so it's definitely not afraid to try new things to make more $$$

  13. Mainstream publishers pay extra money to bookstores (mostly Barnes and Noble these days since Borders is gone) to get certain books placed on those nice display tables at the front of the store. Why shouldn't Amazon adopt a similar model for essentially "paid placement?" These are legitimate concerns for smaller/indie publishers who might not have the budget to shell out money for favored nation status!

  14. hey, i found the ranking company they ranked my product from 17851 to 93 place! it's so cool! amazon ranking service

  15. Looking forward to reading more. idnlive Great blog post.Thanks Again.