Understanding Amazon's BSR in SellerAmp: The Best Sellers Rank & How to Use It

What is BSR?

BSR stands for Best Sellers Rank and is Amazon’s way of showing how a product sells versus other products in the same category. A product with a BSR of 1,000 is the 1,000th best selling product in that category at that moment. BSR’s continually fluctuate with better selling products being re-ranked more frequently.

Since categories are so large, an easier way to reference BSR is the percentile. The lower the percentile, the better the BSR. So a BSR percentile of 2% means that product is in the top 2% of sellers in its category.
Ranks & Prices panel for a product highlighting the Best Sellers Rank percentile

To give you a good perspective on BSR and the number of products in different categories, SellerAmp has a Sales Rank table available for use. It is free and updated daily! 
Sales Rank Table feature in SAS