Adsense

Amazon Kindle Sales Ranking vs Printed Book

Update: I've done a full comparison of Kindle sales ranks vs book sales ranks here.

Several small publishers have told me about their experiences publishing ebooks for the Amazon Kindle reader. Since the number of Kindles in existence is limited to a small subset of the reading population for the time being, you wouldn't expect the per title sales to be particularly high. Books that are available as Kindle ebooks do have the advantage of swimming in a smaller pond, as only a subset of all books have been published in Kindle version, so I was curious to see what the sales ranks were telling us. Since the publishers I know with Kindle sales aren't selling large numbers of books, I spent some time searching for a Rosetta stone. The graphs shown below were generate by Charteo.us for an anonymous title (I removed the name to protect the innocent), for which the Kindle and paper sales volume was identical. The only variance is the magnitude of the peaks, which is due to their being sampled at different times of day.



I counted 12 unique sales over the 3 month period on both graphs. The graphs are on a semi-log scale that doesn't show the gradations, so I'll point out that the Kindle rank doesn't drop below 30,000 during the three months, while the paper book rank drops all the way to a million between sales. Charteo does report the average over the period, which was about 26,000 for the Kindle rank vs 650,000 for the paper book rank. Referring to my graph for estimating the number of copies sold by Amazon sales ranks, a book with an average rank around 26,000 would be selling just under 20 copies a week on Amazon. Without adjusting for seasonality, that suggests that the sales of Kindle ebooks in this part of the ranking curve (from the 1,000's to the 10,000's) amounts to dividing by 20.

But here are some caveats. First, there are far fewer Kindle titles than paper titles available, so the curve is greatly compressed. The lowest Kindle rank I've seen for an ebook that's sold a copy is around 60,000, while nearly a hundred times that number of paper books have ranks. Secondly, there's no reason to believe the relationship holds up for the top sellers. While I found an example that was in the Top 10 at one point (both Kindle and paper) and the sales patterns track perfectly, there were so many sales that the curves become smooth and I can't count peaks to get sales totals. It's also possible that a book selling that many copies would show somewhat proportionate paper and Kindle sales for natural reasons.

I don't know why Amazon has chosen to count sales of Kindle versions together for at least some number of titles. I remember that back in the mid-2004 to mid-2006 period when I sold around 1,000 ebooks through Amazon as PDF's, the ebook sales ranks were entirely independent of the paper book sales ranks. At that time, two of my ebooks often broke into Amazon's Top 10 and pretty much lived in the Top 100 while averaging a little under one sale a day each. The danger of extrapolating potential Kindle sales from that experience is twofold. First, anybody with a computer could buy the earlier PDF ebooks, you didn't need a $399.00 Kindle to read them. So the potential market was much bigger. But on the other hand, the Kindle market is somewhat captive. Having spent $399 on the reader, a person has a high motivation to buy something to read on it.

I haven't seen Amazon publicly report on the number of Kindle units sold. I'd be surprised if they hadn't sold tens of thousands by this point, but I'd be equally surprised if they've sold hundreds of thousands, since I haven't stumbled across anybody using one yet. I also found the relative lack of correlation between the New York Times Bestseller list and the Kindle Bestseller list interesting.

[Friday April 18th edit]

I think this is the first time I've ever gone back and added to a post, and that despite the fact that nobody is interested:-) Some further research convinces me that the title I used for a test case sold primarily in the paper version, perhaps only a single Kindle copy was sold. That would change the Kindle sales rank equivalency to a ratio closer to 1:200 in the 1000's to 10,000's part of the curve. It's starting to look to me like Amazon starts showing a Kindle rank as soon as a copy is sold, and from there it just tracks the paper rank in some relationship.

8 comments:

Morris Rosenthal said...

Morris,

After walking around for a couple of hours, I can think of all sorts of things that might be wrong with my conclusions. For example, the book in question may NEVER have sold a Kindle copy, it may be gifted with a Kindle equivalent rank just for existing, or for having sold one copy.

Based on my guesstimate of the number of Kindle readers in existence, I have to believe that all of the Kindle ranks beyond the top 100 or 1,000 are largely based on sales of their print companions. I just don't find it likely that some tens of thousands of Kindle owners (my estimate) have already bought over 50,000 unique titles. But Amazon has surprised me before.

Morris

Steve said...

Hi Morris,

Here's some data that might be useful, because it focuses on a title that for all intents and purposes is **only** sold as a Kindle edition, but is tracked both in terms of its Kindle store sales rank **and** its rank as a nonfiction title in the main store.

My title "How to Use the Amazon Kindle for Email...." is currentlly #2 in the Kindle store (has been most of the time for the past couple of weeks) and is also now in the top 10 nonfiction titles in the main store. (This latter ranking has occurred only recently as Amazon has shipped a ton of Kindles to catch up with its backlog, and interestingly is not reflected with a ranking among "all books" including fic and nonfic).

The title in question, which is an aggregate of several chapters excerpted from a book on the Kindle as a gadget, had sold 6640 Kindle edition "copies" as of yesterday, and its daily sales for the past 10 days from 4/11 through 4/20 were:
4/11 65
4/12 83
4/13 83
4/14 97
4/15 90
4/16 172
4/17 172
4/18 233
4/19 222
4/20 171

I'm guess that's data worth chewing on for you. For me, it's just a bunch of numbers that signify a better Amazon deposit in late June. For my 9-year-old son, it is "creepy" that there were two sets of repeating totals in a 6-day period.

Best,
Windwalker
http://indiekindle.blogspot.com/

Morris Rosenthal said...

Steve,

Thanks a million. Very chewy numbers. I had seen your book was at #2 when I checked the list last week. Funny to think that the ebook sales had to wait for the Kindle readers to show up:-)

Morris

Steve said...

That's just the thing that gets me a bit jazzed about the potential here: what we are looking at is at any given time a finite set of buyers/readers/customers whom we might expect to grow at, say, a logarithmic year-over-year pace. But you are the one who possesses the tools and the intellect to speculate about that pace and how many Kindles might be involved.

I was disappointed that Amazon said nothing to quantify the Kindle universe at its Jan 30 conf call, but after Jeff's shareholder letter the other day I am again hopeful that next week's conf call might include some numbers. I figure the conf call or the accompanying data dump is the only forum where they can legally speak of such things.

Best,
Windwalker
http://indiekindle.blogspot.com/

Errol R. Williams said...

I'll add to this post by saying, from my observations I have noticed that the Sales Rank for Kindle Books, are not totally dependent on unit sales, but also other factors such as - the listed price, its genre/category and if the Kindle title is linked to its physical paper/hardback edition on Amazon.com.

For example: - one of my listed Kindle titles (not linked to its physical book edition) priced at $0.80 had an average 7-30 days Kindle Sales Rank of 10,000+. End of month sales were - 42 units

Another title I have listed (linked to its physical book edition) was priced at $14.95, average 7-30 days Kindle Sales Rank, 650 - 1500, end of month sales were, 12 units.

So despite having a much better Amazon sales rank in the Kindle Store, it only sold 12 units, compared to 42 units for the first title.

I personally think the biggest factors which influence a titles Sales Rank in the Kindle Store are the listed price, units sold, and the Kindle title being linked to its physical book edition.

So because a Kindle title has a lower Sales Rank, does not mean it has sold more copies than a title with a higher Sales Rank.

Morris Rosenthal said...

Errol,

I've never seen any indication that price affects sales rank. I think you're seeing two variables in an equation (price and paperback sales) and assuming that they both have to have an impact. My own take, based on following this stuff for ten years, is that all of the difference you're seeing is made up by the paperback sales and the other sales rank factors, such as timing and context.

Your conclusion that a Kindle with a lower sales rank hasn't sold more copies than another Kindle is correct for the reason above, but even more so for the standard sales rank reasons. The strong history component of sales rank was dropped way back in 2004, it's primarily a "what have you done for me lately" measure at this point that only has value if averaged over a long time period or in comparison to other top sellers with steady ranks.

Morris

Errol R. Williams said...

Morris,

What is your guess to what actually happened in the following scenario: A listed Kindle title of mine had a Sales Rank of 1,564. Within the next hour, its Sales Rank dropped to 88 in the Kindle Store. The next following hour, its Sales Rank returned to 1,564.

I noticed this also happened for several other Kindle titles at the same time as my listed title.

Errol R. Williams

Morris Rosenthal said...

Errol,

I'd guess it sold a copy or they updated the algo or recrunched some data.

Beyond that, there's not enough information to say anything. When I'm working on rank charts, I watch a number of titles day and night over a period of time to see the relative moves. It helps if you have multiple titles of your own in the same range to watch, with good tracking as to real-time sales through Amazon.

If you're looking at sales ranks to try to figure out what happened at a particular time on a particular day, you're barking up the wrong tree. Not only does the system sometimes freeze or stagger, but like all software platforms that are continually modified, things glitch.

Morris