Most writers, especially those of the self-published variety, watch their Amazon ranks as they fluctuate from day to day, hour to hour with some degree of frustration and puzzlement. I think a common misconception is that rank is directly tied to X number of sales. That is true to a certain extent, but it is a very fluid tie. On Monday you may sell 10 books in one hour and that might bring your rank down to # 4,500 for that hour, but then, the next hour you might sell 15 books and your rank will take an unwanted dive to # 5,100. What can we possibly glean from that? Can we look at any author's rank and tell exactly how many books they've sold to achieve that rank? No! No, no, no!
Amazon's ranks are simultaneously indicative of how many copies of your book sold in the previous hour AS WELL AS how many of your competitors' books sold during that same hour. If you are lucky enough to have been one of only a few who sold 10 copies in that first hour, then your rank will shoot up. If you sold 10, but someone else managed to sell 25 in that same hour, your rank will likely drop as a result. The rank is not just a measure of your sales, but a measure of your sales in comparison to other books' sales.
I know a very popular and wildly successful author once posted that in order to achieve X low rank she sold Y number of books in Z period of time. It's unlikely that that would ever happen again, for in order for that to be the case, every single component of that time period would have to be repeated identically. You see what I mean? Good ranks on any given day, at any given hour are the result of the perfect storm of great sales on your part and similar or not-so-good sales on the part of your competitors.
Some days you might sell 2 books and see a 10K rise in rank, depending on how high or low your rank is to begin with. Another thing I've discovered is that the lower your rank, the harder it is to make a significant move forward. The lower you get, the higher your sales. And the higher your sales, the greater your competition. When you drop below #1000, you are competing with some pretty heavy hitters. That's even more the case when you drop below #500. Needless to say, when you drop below #100, you're in the shark tank. You're in the company of such authors as James Patterson, John Locke, Amanda Hocking, Charlaine Harris, Lee Child, Michael Connelly and Nora Roberts. Rank fluctuations in those esteemed positions tend to be very tight. They're also very hard to maintain. You have to be raking in some serious sales to hang with those guys. But can it be done? Absolutely! It's just a frustrating, nail-biting, hair-pulling ride to get there.
All in all, when you look at a rank, it doesn't really start painting a very telling picture until you get pretty low. It's safe to assume that when you see someone in the low hundreds or, even better, below #100, they're really selling some books. Around #200-300, you can expect that they're selling hundreds per day, a thousand or better per week. But when you get even lower, like below #100, those lucky people are selling possibly thousands per day. Those are the ones I look at and say, "Wow!" Take John Locke for instance. Though he has 9 books, he sells a copy every 7 seconds. That's roughly 9 per minute, 540 per hour, 12,960 per day, 90,720 per week, 362,880 per month and roughly 4.5 million per year, give or take a few thousand.
I think, armed with that knowledge, we have to congratulate all the authors who see the low ranks on Amazon for their amazing success. The hard work that got them there is nothing to sneeze at and neither are the results.