Our sales rank is just like a bestseller list, except instead of listing just the top 50 or so titles, it includes millions! The lower the number, the higher the popularity for that particular title in comparison to other items listed. Items are ranked within their product category only, so a book, CD or DVD ranked at Number 1 is the best-selling book, CD or DVD at Amazon.com, but may not be the overall best-selling item.
Sales rank data is calculated hourly. While we cannot provide specific information about our calculation formula, Amazon.com Marketplace sales are also included in the calculation. Please keep in mind that our sales rank figures are simply meant to be a guide of general interest for the customer and not definitive sales information for vendors – we assume you have this information regularly from your distribution sources.