About the BSR Sales Estimator
Every book on Amazon shows a Best Sellers Rank (BSR), but Amazon does not say how many copies that rank represents. Authors use BSR to size up a niche, gauge a competitor or check the effect of a promotion, and a sales estimate makes the rank easier to understand.
This estimator converts an overall store rank into an estimated range of daily and monthly sales, plus a plain-language sales tier. It uses separate curves for the Kindle Store and for print books, and scales the result for other Amazon marketplaces. A reference table shows what the model gives for example ranks from #100 to #1,000,000, so you can see how quickly sales drop as rank rises.
Treat the result as a rough guide, not a fact. The model is built from anchor points and interpolation, and real sales at a given rank vary by season, day and category. It works best for comparing books or niches against each other rather than predicting your exact income. Read what Amazon BSR is for more background.
How It Works
The model holds a set of anchor points, each pairing a rank with an estimated number of sales per day. Ranks between anchors are interpolated on a log-log scale, which matches the steep curve of book sales.
For marketplaces outside the US, the US estimate is multiplied by a scaling factor for that store's size. These estimates are less reliable and the tool says so.
The range shown is the midpoint estimate multiplied by a low and a high factor. Monthly figures assume 30 days at the same rank.
Formula
- Interpolation
- log(Sales) is interpolated linearly against log(Rank) between anchor points
- Range
- Daily range = Estimate × Low factor to Estimate × High factor
- Monthly
- Monthly sales ≈ Daily sales × 30
Example
An eBook ranked #25,000 in the Kindle Store on Amazon.com
- #25,000 sits between the model's anchors at #10,000 and #50,000.
- Log-log interpolation gives a midpoint of about 7.5 sales per day.
- Applying the range factors gives 4.5 to 11.2 sales per day.
- Over 30 days that is about 134 to 336 sales, a 'Steady seller' tier.
A #25,000 Kindle rank suggests roughly 4.5 to 11.2 sales a day, or 134 to 336 a month.
Important Notes
- Estimates come from a model, not from Amazon data. Real sales at any rank can be much higher or lower.
- BSR updates hourly and reflects recent sales, so one reading is only a snapshot. Check a rank several times before drawing conclusions.
- Use the overall store rank only. Sub-category ranks (such as #3 in a niche category) are not supported.
- Kindle ranks include Kindle Unlimited borrows, so some estimated 'sales' may be page reads rather than purchases.
- Non-US marketplaces use a simple size factor and are less reliable than US estimates.
Frequently Asked Questions
How accurate are BSR sales estimates?
They are approximate. Any estimator, including this one, models the relationship between rank and sales from limited data. Use the range rather than the midpoint, and compare books against each other rather than relying on one number.
Why can't I use a category rank?
Category ranks only compare a book with others in that category, and categories vary hugely in size. A #1 in a tiny niche can sell fewer copies than #50 in a large one. The model is built for overall store ranks.
Why do Kindle and print estimates differ for the same rank?
The Kindle Store and the Books (print) store have different numbers of titles and different buying patterns, so the same rank represents different sales volumes. The estimator uses a separate curve for each.
Why did my rank jump after a single sale?
At high rank numbers, few sales separate books, so one sale can move a book up by hundreds of thousands of places. The rank then drifts back down until the next sale.
Which marketplaces are supported?
The marketplaces listed in the dropdown. Each uses a scaling factor relative to Amazon.com, so the larger the store, the more reliable the estimate.
Can I estimate income from BSR?
Combine the estimated monthly sales with your royalty per sale from the [KDP Royalty Calculator](/tools/kdp-royalty-calculator) for a rough income range. Remember that both inputs are estimates.
Related KDP Tools
- KDP Royalty CalculatorEstimate your royalty and profit from Kindle, paperback and hardcover sales.
- KDP Profit CalculatorTurn royalties, ad spend and other costs into net profit, profit per book and margin.
- Kindle Royalty CalculatorCompare the 35% and 70% eBook royalty options including delivery costs.
- KDP Keyword FormatterClean a keyword list and pack it into seven KDP keyword fields.
- KDP Pricing CalculatorWork backwards from the profit you want to the list price you need.
- Paperback Pricing CalculatorGet minimum, break-even and recommended paperback prices from page count, trim and ink.
Related Guides
- What Is Amazon BSR? Best Sellers Rank Explained for KDP AuthorsWhat Amazon Best Sellers Rank means, overall vs category rank, why BSR moves so much, how sales estimators work, and how to use BSR for niche research.
- How to Choose KDP Keywords: Filling Your 7 Keyword FieldsHow to choose and format your 7 KDP keyword fields: character limits, phrases vs single words, what to avoid, simple research methods, and formatting tools.