Are you curious how Amazon does its ranking calculation? I pulled this from their website. It’s there official explanation.
What Amazon Bestsellers Rank Means
The Amazon Bestsellers calculation is based on Amazon.com sales and is updated hourly to reflect recent and historical sales of every item sold on Amazon.com.
What Amazon Bestsellers Rank by Category Means
While the Amazon Bestsellers list is a good indicator of how well a product is selling overall, it doesn't always indicate how well an item is selling among other similar items. Category and subcategory bestseller lists were created to highlight an item's rank in the categories or subcategories where it really stands out. We choose a few of the most popular subcategories in which the item has a high ranking in relation to other items in that subcategory, and showcase the item's rank on the product page. As with the main Amazon Bestsellers list, these category rankings are based on Amazon.com sales and are updated hourly.
What an Item's Actual Sales Are
For competitive reasons, Amazon.com generally does not publish this information to the public.
What Paid and Free Amazon Bestsellers Lists Are
For the Kindle Store, Amazon Bestsellers lists are divided into Top 100 Paid and Top 100 Free. Items in the paid bestsellers list have a value greater than $0.00. Items in the free list have a value equal to $0.00. Both lists are updated hourly.
Now these are some interesting stats on book sales. Since the algorithm Amazon uses to generate its sales ranking is proprietary, the details below are extrapolated from research and field tests.
I gave credit to the source at the end of the blog.
If the book’s average ranking is:
2,000,000+ Perhaps a single inventory/consignment copy has been ordered
1,000,000+ Current trends indicate total sales will most likely be under 40
100,000+ Current trends indicate total sales will most likely be under 200
10,000+ Estimate between 1 – 10 copies being sold per week.
1,000+ Estimate between 10 – 100 copies being sold per week.
100+ Estimate between 100 – 200 copies being sold per week.
10+ Estimate between 200 – 1000 copies being sold per week.
Under 10 Estimate over 1,000 copies per week
Brent Sampson is the President & CEO of Outskirts Press Publishing at http://www.outskirtspress.com and author of Publishing Gems: Insider Information for the Self-Publishing Writer. Information at http://outskirtspress.com/publishinggems