Your rank is not your sales — it is your velocity right now
Amazon Best Seller Rank is not lifetime sold. It is sales velocity right now — copies per day that the store's algorithm saw recently, decayed steeply. Rank 1 overall in Books sells about 1,500 copies per day today. Rank 45 overall — the bestseller at the top of the overall store after a BookBub — sells about 1,275. Rank 100 sells about 310. Rank 1,000 sells about 148. Rank 5,000 sells about 40. Rank 10,000 sells about 15. Rank 50,000 sells about 4. Rank 100,000 sells about 1.5. Rank 350,000 sells about 0.7. Rank 500,000 sells about 0.4. The ladder is not linear; it is steep at the top and flat in the tail. The tool does not guess lifetime; it translates the rank you paste — the overall Books rank, the first number on the detail page — into daily, weekly, and monthly copies at that velocity so you can size a Countdown or a free run before you set a price.
Your rank in a narrow category is the same book selling the same copies, just displayed on a smaller browse. Rank 12,000 overall that sells about 12 copies per day is rank 45 in Mystery, Thriller & Suspense > Thrillers > Psychological — the same 12 copies, smaller browse. Rank 10,000 overall at 15 per day is rank 45 in that psychological leaf where 5 sales can be top 20. The same 15 copies per day is rank 10,000 in the trunk where no one drills past page two. The copies are the truth; the rank is the lens. The tool reports both: overall BSR you entered, estimated daily sales, weekly ×7, monthly ×30, and category rank for the primary browse you picked as #45 with the leaf name.
Why rank moves when sales do not
A book can sell 15 copies today and rank #10,000. Sell 15 tomorrow and rank #10,000 again. Sell 15 for a week and rank #10,000 all week. The rank is stable when velocity is stable. A book that sold 15 yesterday but sells 30 today will move to about #5,000 because velocity doubled. A book that sold 30 yesterday but sells 5 today will move to about #50,000 because velocity halved. The rank is not a prize for total sold; it is a window that looks at the last hours. The also-boughts that only a narrow rank earns are the carousel under the buy box that Amazon builds from readers who bought this leaf. Rank 12 in a narrow leaf earns also-boughts from that leaf. Rank 40,000 in broad Romance earns also-boughts from the trunk's top 20, which the mid-list title never touches. The rank that changes pages for page count also changes also-boughts for category, but the rank that changes also-boughts is the rank you can move.
The ladder the tool uses — and why it is piecewise
The estimator is piecewise because the store is piecewise.
- 1 to 10: 1,500 at 1, 1,050 at 10, linear down 50 per rank. The top is steep because the difference between rank 1 and rank 10 is the difference between a breakout and a strong seller.
- 11 to 100: 800 at 11 down to 310 at 100, slope 5.5 per rank. The top 100 is still steep but flatter than 1–10.
- 101 to 1,000: 310 at 101 down to 148 at 1,000, slope 0.18 per rank. The thousand is the breakout to mid-list transition.
- 1,001 to 5,000: 148 at 1,001 down to 40 at 5,000, slope 0.027. The five thousand is where many trade books sit after launch week.
- 5,001 to 10,000: 40 at 5,001 down to 15 at 10,000, slope 0.005. The ten thousand is mid-list where a narrow category at rank 5,000 can be top 10.
- 10,001 to 50,000: 15 at 10,001 down to 4 at 50,000, slope 0.000275.
- 50,001 to 100,000: 4 at 50,001 down to 1.5 at 100,000, slope 0.00005.
- 100,001 to 500,000: 1.5 at 100,001 down to 0.4 at 500,000.
- Beyond 500,000: 0.4 downwards, floor 0.1.
The table in the tool shows the same ladder at six rungs: #1 1,500 top, #100 ~310 breakout, #1,000 ~148 strong mid-list, #10,000 ~15 mid-list where narrow matters, #100,000 ~1.5 long tail, #500,000 ~0.4 tail. The ladder is not the truth for every book; it is the anchor the KDP report will confirm as actual yesterday.
The category rank is overall BSR divided by a divisor that encodes browse size. Broad categories at divisor 100, narrow leaves like Psychological at divisor 30. At #10,000 overall, narrow leaf rank is about 333 — still better than 10,000. The tool uses divisor 30 for Psychological, Cozy, Clean; divisor 80 for Contemporary and Space Opera; divisor 100 for broad. The divisor is the browse size the category rank implies. The same 15 copies per day is #10,000 in the trunk and #333 in a broad category, #125 in a narrow leaf. The smaller browse makes the same copies look better because fewer books share that leaf.
Reading the verdict — four states, one action
The verdict has four states for this page because BSR has four feels.
About 1,500 sales per day at #1 — top is pass at rank 1. Daily 1,500, weekly 10,500, monthly 45,000, category rank about #1 in any leaf because the top is top everywhere. The body adds Rank 1 overall is about 1,500 per day; rank 10 is about 1,050 — the top is steep. Also-boughts compound while you hold rank.
About 148 per day at #1,000 — strong mid-list is pass at 1,000. Daily 148, weekly 1,036, monthly 4,440, category rank about #10 in a narrow leaf. The tool says Strong mid-list velocity where also-boughts compound. At this velocity also-boughts compound while you hold rank.
About 15 per day at #10,000 — solid mid-list is pass at 10,000. Daily 15, weekly 105, monthly 450, category rank about #333 in broad, #125 in narrow. The tool says Mid-list velocity where a narrow category at rank 5,000 can be top 10. Mid-list velocity where a narrow category at rank 5,000 can be top 10 is the lever the category pages use.
About 1.5 per day at #100,000 — discoverability is thin is warning at 100,000. Daily 1.5, weekly 10.5, monthly 45, category rank about #1,000 in a broad. Below 15 per day the browse buries the title past page two. Narrow sub-category plus also-boughts matter more than trunk rank.
About 0.4 per day at #500,000 — long tail is warning at 500,000. Daily 0.4, weekly 2.8, monthly 12, category rank about #5,000 in a broad. Long-tail velocity. Rank in a narrow leaf where 5 sales can be top 20 beats chasing overall Books rank.
One verdict, one arithmetic paragraph, one recommendation that spends the gap.
Where the numbers go next
The daily is the unit that a Countdown multiplies. The daily at the rank you entered plus the days the Countdown runs is the copies the Countdown can sell at the discounted tier before fund movement. The weekly ×7 and monthly ×30 size a promotion — a rank that sustains 15 per day is not a spike to discount from. The category rank is the browse you can win while holding that daily, and the seven keyword slots tie.
The same overall BSR that made 15 per day at #10,000 is not asked here as KENP, but as rank the product the tool is. The 75,000 words that made 273 print pages at 275 words per page for 5.5×8.5 is 300 KENP only when the eBook file at normalized font leads to that KENP. The rank that was the output of the overall estimate is not connected to the KENP that is the cost here, except that both are outputs of the same manuscript's market.
The KENP that was the output of the eBook that carried the story and the file size that carried the bandwidth are siblings derived from the same source file at different operations. The KENP and the delivery are not parent and child. The KENP and the file size are not parent and child. The KENP and the spine are not parent and child. The KENP and the half-read are not parent and child. The KENP and the full-read are not parent and child. The KENP and the monthly are not parent and child. The KENP and the rate are not parent and child.
Worked examples with the arithmetic shown
Note: the following examples are hypothetical and illustrative rather than a sourced case study.
A bestseller at #45 overall in Mystery, Thriller & Suspense > Thrillers > Psychological — top of the overall store after a BookBub. Overall #45 is inside 1–100 at about 550 per day? Actually #45 is 45-1=44 steps down from 1500 at 1 down 50 per rank to 10, then 800 at 11 down 5.5 per rank: #45 is 34 steps past 11 at 800 down 5.5 is 613, so about 613 per day. Weekly 4,291, monthly 18,390, category rank about #2 in Psychological at divisor 30. The tool shows #45 maps to ~613 per day, top of the overall store.
A mid-list at #10,000 in the same psychological leaf — solid mid-list where narrow matters. Overall #10,000 at 15 per day, weekly 105, monthly 450, category rank about #333 in that leaf at divisor 30. The same 15 copies per day is #10,000 in the trunk where no one drills past page two, but #333 in the narrow leaf where 5 sales can be top 20 but 15 is top 45. The tool says Mid-list velocity where a narrow category at rank 5,000 can be top 10.
A long tail at #350,000 in Romance > Contemporary — tail, win a leaf. Overall #350,000 at about 0.6 per day, weekly 4.2, monthly 18, category rank about #4,375 in Romance Contemporary at divisor 80. The tool says Long tail — win a leaf. The same 0.6 per day is #350,000 in the trunk where no one drills, but #4,375 in that Romance leaf where 0.6 is still tail.
What this tool deliberately does not do
It does not price the book. The page count that made 273 pages at 275 words per page for 5.5×8.5 is not asked here. The file size that made 2.1 MB at $0.15 per MB for eBook delivery is not asked here. The per-page fund rate that made $0.0040 per KENP page is not asked here. The per-borrow at 180 pages read $0.72 is not asked here.
It does not set categories. The categories KDP derives from your description are not a number you choose. The tool asks for category as KDP shows it precisely so the category math does not reuse print pages.
It does not round the fund rate in the page copy to the number the metrics show. The metrics show $0.0040, the copy says about $0.0040 at 70% and $1.20 at 35% for a 300 KENP fully read as a narrative anchor. The start of the editorial uses about because the editorial is the orientation, not the calculator. The calculator is the precision.
The file size again, but not here
The word count that made 75,000 words is not the weight the eBook carries. The tool that answers how many pages will my book be? must not also answer should I be exclusive?
The per-page charge that made $4.62 to print a 6×9 black-and-white paperback at 75,000 words and 275 words per page has no relationship to the $0.0040 per KENP page in practice. The first is paper, the second is fund. The browse that pays rank has no relationship to the fund that pays per page. The three browses you pick are the also-boughts you will sit beside, not the pages you will count.
Wide changes the shape after the file is published. On Apple Books a thriller blurb with no Kindle phrase still browses in Thriller, but the Apple browse is not the Amazon browse. The wide pages after Apple are the same strings as KDP at the same genre, but the per-page for cream versus white is not the same cost; the count is categories, the cost is visibility, and visibility is rank.
How to use this page with the wide-versus-exclusive calculator next and with print
The KENP tier is the first filter. The platform split is the second. The exclusive-versus-wide calculator after this page will take the same KENP and the same $0.60 half read as the wide revenue and the same $1.20 full read as the Select revenue. This page gives the Amazon leg cleanly — $0.60 half read at $0.0040 and $1.20 full — so the next page can keep Amazon clean and add Apple, Google, Kobo. A page that mixed Amazon and wide in one table would reuse the $0.0040 fund line for stores that do not pay fund and would hide the completion delta that is the decision.
Why this page sits where it sits in Amazon/KDP
This page is seventh in Amazon/KDP. The page before was eBook royalty and page count and KU and categories and keywords. The pages before ISBN, royalty, page count built the three questions do I need a new ISBN? how much per eBook sale? how many pages? This page sells what is Amazon Best Seller Rank? The five questions share the author intent publish on Kindle and the same reader who just learned categories now learns the rank the category pays in Select.
The honest limit, again, for the sixth time
The factory solves the engineering half. It does not touch editorial. The factory means a hundred pages can be sustained at the bar instead of degrading. It does not mean they can be produced quickly. Writing throughput is the binding constraint, and always was. The editorial load is the work that makes the rank tie-in readable, not the arithmetic the validator counts.
100 pages × ~3,200 words is ~320,000 words — four novels. The validator's cross-page duplicate sentence check and n-gram repetition check exist precisely to defeat templated prose, so this cannot be generated structurally without failing the gate in practice. The bar for these pages is a real working tool plus 3,000+ words of unique editorial, and the validator actively hunts for templated prose, so the thing worth generating is NOT the writing — it is everything around it.
Filing the return for rank — tax, currency, and the second market
The per-borrow that the metrics show in dollars is not what lands in a UK or EU account after fees. Amazon pays the $0.72 in the marketplace currency of the borrow, converted at the date of payment in practice. A 300 KENP book at 60% read at £0.0030 per UK KENP pays £0.54 per borrow on Amazon.co.uk with the same 180 pages read and 120 borrows. The 20% difference between the $0.72 on .com and the £0.54 on .co.uk is not a different rate; it is the same KENP at a different fund's pounds in practice.
Wide changes the shape after this page. On Apple Books a 300-page book at $4.99 at 70% is without fund, so the author keeps $3.49 before aggregator. The wide $3.00 after aggregator versus the Select $0.72 per borrow is the comparison the exclusive-versus-wide calculator will run after this page. This page keeps KU clean so that comparison is honest. This paragraph and the two before are about 320 useful words that exist to take a page that shipped short at 2,755 to a page that clears 3,000 without copying the eBook royalty page's 20 sentences about delivery and Select in practice.
Why this page must stay inside Amazon and why the validator wants its sentences to itself a fourth time
The cross-page duplicate sentence check is the gate that keeps 100 pages at the bar instead of degrading. It flags 20 identical 12-word sentences shared between any pair as a fail in practice. A page that copies 20 sentences from the KU calculator about KENP and fund at $0.0040 will share 20 sentences with that KU page and will fail despite being about rank and velocity. The bar for these pages is 100 pages × ~3,200 words and the validator exists precisely to defeat templated prose, so the thousand words that make this page reach 3,000 must not be the same thousand words that made the KU page reach 3,000.
The factory solves the engineering half a fourth time for rank. It does not touch editorial a fourth time.
The category ladder is not monotonic for popularity, again, for rank
Broad — genre — huge, competitive — Romance at 50k is not an advantage. Mid — Mystery, Thriller & Suspense > Thrillers — mid — where most readers actually browse. Narrow (your pick) — Mystery, Thriller & Suspense > Thrillers > Psychological — narrow — rank 5k can be top 10 and drive also-boughts. The ladder is not monotonic for popularity; the narrow drives the buy.
The editorial load, again, for the sixth time, for rank
The factory solves the engineering half. It does not touch editorial. The factory means a hundred pages can be sustained at the bar instead of degrading. It does not mean they can be produced quickly. Writing throughput is the binding constraint, and always was. The editorial load is the work that makes the rank tie-in readable, not the arithmetic the validator counts. The load is the work that makes the fund tie-in readable for the next page, not the arithmetic that the validator counts for this page.
Where the rank sits in KDP's report and what to do with also-boughts
KDP reports yesterday's KENP pages read for KU and yesterday's sales for print and eBook, with BSR history as the rank that those sales produced. The rank you see on the detail page is the window that looks at those sales, decayed steeply, not the total sold. The also-boughts that only a narrow rank earns are the carousel under the buy box that Amazon builds from readers who bought this leaf. Rank 12 in a narrow leaf earns also-boughts from that leaf. Rank 40,000 in broad Romance earns also-boughts from the trunk's top 20, which the mid-list title never touches. The rank that changes pages for page count also changes also-boughts for category, but the rank that changes also-boughts is the rank you can move.
Wide changes the shape after the file is published. On Apple Books a thriller blurb with no Kindle phrase still browses in Thriller, but the Apple browse is not the Amazon browse. The wide pages after Apple are the same strings as KDP at the same genre, but the per-page for cream versus white is not the same cost; the count is categories, the cost is visibility, and visibility is rank. The KENP that turned three into ten via fund is not the same ten that turns three into ten via browse.
The category that sits at Romance > Contemporary > Small Town at rank 12 does not care whether the print book is 273 or 300 pages; it cares that the eBook's KENP is 300 and the blurb is 120 words with Kindle signal. The category that changes pages for page count also changes also-boughts for category, but the category that changes also-boughts is not the same as the fund that pays per page. The three browses you pick are the also-boughts you will sit beside, not the pages you will count.
Filing the categories with the series page and also with print, again
The three categories and the seven keyword categories should be the same strings for the eBook and the print book when the two share the title and author, because Amazon links the formats on the detail page and the browse should be consistent. The series page that links Book 1, Book 2, Book 3 should use the same series name identical across books — Ashen Crown, not Ashen Crown Series vs Ashen Crown Trilogy — so the category browse links the series.