What is Amazon BSR and how is it calculated?
Best Sellers Rank (BSR) is a category ranking updated hourly based on recent and historical sales velocity in that category. A BSR of 1 is the top seller in the category. Recent sales weigh most, but historical velocity keeps rankings stable so a single spike does not flip the top spot.
Jul 26, 2026 · 3 min read
The inputs Amazon uses
Recent unit sales in that specific category, historical sales over the past weeks and months, and category size. Amazon does not publish the exact formula, but recency dominates: a strong 24-hour push can move BSR sharply, then it decays over days.
Because rank decays quickly, a single snapshot tells you little. Nova keeps a daily rank history for your own ASINs so you can see whether a drop followed a price change, a stockout or a competitor push.
BSR per category, not per ASIN
A product can have a BSR in its main category and in each subcategory it appears in. The main category BSR is what shoppers see on the detail page.
What BSR is not
It is not a direct sales-volume number. Category size, price band, and competition mean BSR 500 in one category can equal BSR 50,000 in another in unit terms.
Frequently asked questions
How often does BSR update?
Hourly, though the main category BSR displayed publicly can lag by a few hours.
Do refunds affect BSR?
Yes. Refunded units are excluded from the sales counted toward BSR.
Do FBM sales count toward BSR?
Yes. BSR includes all sales of the ASIN regardless of fulfilment method.
Does Nova track my own BSR?
Yes. Nova tracks BSR history for your own ASINs (Nova does not track competitor BSR).
See this in Nova
Nova surfaces this metric per SKU so you can act before your next monthly close catches it.
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