A cover price that tests is not the same as a cover price that holds on thumbnail
An eBook premade at $49 to $149 buys a single front cover. A paperback premade at $79 to $199 buys front plus spine plus back plus bleed. A hardcover jacket premade at $99 to $249 buys a jacket with flaps plus spine. A custom eBook at $300 to $800 buys a single front tailored to your title and subtitle, a paperback custom at $400 to $1,200 buys a front that holds at 160px thumbnail where the title is 3 words not 7 plus a spine at 0.625 where the title must fit at 8pt plus a back with blurbs that sell the click, a hardcover jacket custom at $600 to $1,800 buys the same plus flaps where the jacket wraps the case. A $0 DIY where the time is cost buys a Canva export at 300 dpi with bleed where genre convention may not hold.
The checker asks format where eBook only is a single front, paperback is front plus spine plus back plus bleed, and hardcover jacket is with flaps, and goal where quick is test market where premade is the spend that tests without overpaying, mid is series start where custom is the quality that holds on thumbnail and spine, and premium is hardcover or award where custom is required. The model is intentionally small: format selects the premade and custom ranges and the note that explains what the file includes, goal selects the pick where quick is premade, mid is custom, premium is custom, and the averages premadeMid and customMid are the mid of each range that the metrics show. At eBook quick $49 to $149 average $99 is premade, at paperback mid $400 to $1,200 average $800 is custom, at hardcover jacket premium $600 to $1,800 average $1,200 is custom.
Finished hours, price times platform share, sample windows, and SAY sheets all live elsewhere. A nine-hour thriller at $275 PFH is $2,475 production before the first sale, at $19.99 exclusive $8.00 per sale at 40 sales is $320 per month, the sample 5:00 at 63:00–68:00 is where the hook is heard, and the SAY KAEL-en is how it is said when the hook is spoken. A cover budget is none of those; it is whether the file you upload will hold at thumbnail and on spine.
How the budget is built — format sets the ranges, goal sets the pick
Format eBook label single front, premade low 49 high 149 custom low 300 high 800 note single front, paperback front plus spine plus back plus bleed low 79 high 199 custom 400 to 1200, hardcover jacket with flaps low 99 high 249 custom 600 to 1800. At eBook $49 to $149 average $99, paperback $79 to $199 average $139, hardcover $99 to $249 average $174. At eBook custom $300 to $800 average $550, paperback $400 to $1,200 average $800, hardcover $600 to $1,800 average $1,200.
Goal quick, mid, premium selects the pick where quick is test market premade at premadeMid, mid is series start custom at customMid, premium is custom at customMid to customHigh. At eBook quick premade $99 is the spend that tests without overpaying where quick test market is the sell, at eBook mid custom $550 is the quality that holds on thumbnail and spine where premade stretches. At paperback quick premade $139, mid custom $800, premium custom $800 to $1,200. At hardcover quick premade $174 warning but custom $1,200 is safer where hardcover jacket custom handles spine plus flaps plus bleed where premade stretches.
Diy is zero dollars where time is cost only, not a file that holds. A $0 DIY where the time is cost only buys a Canva export at 300 dpi with bleed where genre convention may not hold. The tool does not move words; it moves pick.
The verdict logic reads format and goal together. Quick as eBook or paperback is pass premade, quick as hardcover is warning hardcover jacket premade exists but custom is safer where hardcover jacket premade stretches at flaps. Mid as eBook or paperback or hardcover is pass custom. Premium as eBook is warning premium as eBook still recommends custom where thumbnail and genre convention matter, not just paper.
The calculator is deterministic. The same format and goal always give the same premadeMid, customMid, and pick, because the ranges are fixed. Everything is calculated in your browser. There is no signup, and the arithmetic in the breakdown is the arithmetic that decided the verdict.
Reading the verdict — premade for quick test, custom for mid series, custom for premium hardcover
Premade for quick test market: headline reads "eBook only — premade at $99: Quick test market — premade at $99 is the spend that tests without overpaying." Body names the ranges and the averages. Premade for quick at $99 saves $451 versus custom $550 where the test is whether the book sells before the series is built, not whether the cover holds on spine.
Custom for mid series: headline reads "Paperback — custom at $800: Mid series — custom at $800 is the quality that holds on thumbnail and spine." Body names the ranges. Mid series at $800 is the quality that holds on thumbnail at 160px and spine at 0.625 where premade stretches and where the title is 3 words not 7 plus a spine at 0.625. The $800 custom $400 to $1,200 average $800 is $661 more than premade $139 where genre mismatch where the cover must sell the click is the risk.
Custom for premium hardcover: headline reads "Hardcover jacket — custom at $1,200: Premium — custom at $1,200 to $1,800 is required for hardcover jacket flaps and spine at 16pt large print." Body names the ranges. Premium at $1,200 is required for hardcover jacket flaps and spine at 16pt large print where premade at $174 stretches.
Quick as hardcover warning: headline reads "Hardcover jacket premade $174 exists but custom $1,200 is safer." Body says premade $99 to $249 is available but hardcover jacket custom $600 to $1,800 handles spine plus flaps plus bleed where premade stretches. Quick still picks premade but warns.
Premium as eBook warning: headline reads "Premium as eBook — custom $550 recommended even for eBook." Body says premium goal at eBook still recommends custom $300 to $800 average $550 where thumbnail and genre convention matter, not just paper.
Each result returns metrics for premade, custom, DIY, and pick, a breakdown of the four build rows, tailored recommendations, the table of format times cost at a glance (eBook $49–$149 $300–$800, paperback $79–$199 $400–$1,200, hardcover $99–$249 $600–$1,800), and related links that remain inside the cover flow.
Why premade is the spend that tests and custom is the spend that holds
Premade at $99 average for eBook quick is the spend that tests without overpaying where the test is whether the book sells before the series is built. Custom at $550 average for eBook mid is $451 more where the series start must hold on thumbnail and genre convention. The same eBook quick versus mid is $99 versus $550 at the same format where quick is premade-acceptable and mid is custom-recommended. The same paperback quick $139 versus mid $800 is $661 more where the mid must hold on thumbnail and spine.
A paperback premade at $79 to $199 average $139 buys front plus spine plus back plus bleed but not tailored to your title and subtitle. A paperback custom at $400 to $1,200 average $800 buys a front tailored to your title and subtitle where the title is 3 words not 7 plus a spine at 0.625 where the title must fit at 8pt plus a back with blurbs that sell the click. A hardcover jacket premade at $99 to $249 average $174 buys a jacket with flaps plus spine, a hardcover custom at $600 to $1,800 average $1,200 buys the same plus flaps where the jacket wraps the case.
The KENP that makes Kindle Unlimited pay $0.0040 per page and the print pages that make 273 pages at 6×9 are pages, not cover. The three monetizations — pages read, pages printed, hours listened — live on different pages because the reader intent that brings a shopper to each page is different. The cover at 12.926 wide at 6×9 on white 50# at 300 pages is the print geometry; the cover at $99 premade versus $800 custom is the spend that holds at thumbnail.
Worked examples with the cost shown, hypothetical and illustrative
Note: the following examples are hypothetical and illustrative rather than a sourced case study. Every cost is produced by the same format-goal arithmetic the tool runs.
Example one is paperback mid — custom $800 average. Format paperback premade $79 to $199 average $139 custom $400 to $1,200 average $800 pick custom mid. At paperback mid $800 is the quality that holds on thumbnail at 160px and spine at 0.625 where premade stretches.
Example two is eBook quick — premade $99 average. Format eBook premade $49 to $149 average $99 custom $300 to $800 average $550 pick premade quick. At eBook quick $99 is the spend that tests without overpaying.
Example three is hardcover premium — custom $1,200 average. Format hardcover premade $99 to $249 average $174 custom $600 to $1,800 average $1,200 pick custom premium. At hardcover premium $1,200 is required for hardcover jacket flaps and spine at 16pt large print where premade at $174 stretches.
Where the numbers go next — beyond cover into series, length, and price
Cover cost that is $99 premade versus $800 custom is the file that makes 250 print pages at 6×9 is the print geometry; the series title "Chronicles" on three books is the store geometry. A three-book thriller series where book one at $3.99 with series linking drives read-through to book two at 60% and book three at 40% has a different cover ROI than the same three without linking where read-through loses the carousel. The large print that is 395 pages at 16pt on white paper before retail share is the same trim where the regular 273 sits; the store geometry matters.
Finished hours, price times platform share, sample windows, and SAY sheets all live elsewhere. A nine-hour thriller at $275 PFH is $2,475 production before the first sale, at $19.99 exclusive $8.00 per sale at 40 sales is $320 per month, the sample 5:00 at 63:00–68:00 is where the hook is heard, and the SAY KAEL-en is how it is said. A cover budget is none of those; it is whether the file you upload will hold at thumbnail and on spine and whether large print 16pt needs extra.
Common mistakes are assuming all genres sell cover equally, filing large print at 14pt, treating 150 readers 55 plus as enough. The checker that priced paperback at $16.99 and sized the cover at 12.926 wide are paper geometry; the cover budget is not characters, it is whether the file holds at thumbnail.
Common mistakes and how to avoid them
Assuming premade quality holds on spine is most common. So is assuming DIY with Canva holds on thumbnail where genre convention matters. So is assuming price does not matter. Below $2.99 Kindle pays 35% royalty, not 70%.
Using word count from the proposal instead of the finished manuscript is fourth. Draft 110,000 edited to 80,000 is $11k translation not $15k.
Treating 150 readers 55 plus as enough is fifth. Below 150 large print demand starts, not converts.
Filing the cover — where in KDP you upload the file that holds
You file the cover on KDP under Paperback Content front cover and Hardcover jacket, not on the pricing tab. The fields that must match verbatim across the series for the Series Page are not here; cover can differ per book but then read-through mixes.
If you distribute wide via Findaway or IngramSpark, the cover for Apple Books may render slightly differently, but the cost per word does not change by retailer.
Final checks before you buy the cover
Pick format (eBook only, paperback front+spine+back+bleed, or hardcover jacket with flaps), pick goal (quick test market premade ok, mid series start custom recommended, premium custom required), read premade vs custom vs DIY where time is cost, budget the pick where premade for quick, custom for mid/premium where thumbnail and spine must hold.
How Amazon mobile renders cover thumbnail differently than desktop
Mobile product pages on the Amazon app render the cover as a thumbnail at 160px with the title, author, rating, and cover above and the description below. The app's cover thumbnail at 160px shows the title legibility where the title is 3 words not 7. Desktop detail pages show the cover in the full content column with more title per line at larger size. A cover that is premade at $99 for eBook quick where the title is 3 words not 7 holds at 160px where the title is 3 words, but a paperback custom at $800 for mid series where the spine at 0.625 must fit at 8pt is the quality that holds on spine as well as thumbnail. The tool does not distinguish mobile vs desktop in its pick; it reports one pick because the cover it recommends — premade for quick, custom for mid/premium — converts on both. The HTML you paste in KDP Description — bold hook plus bullets — is the same on both form factors, but the cover file that holds at thumbnail is not HTML.
The Select enrollment on KDP in KDP Select enrollment, not on the pricing tab. The price you enter on the pricing tab sets royalty at 70% inside $2.99–$9.99 regardless of Select. The fields that must match verbatim across the series for the Series Page are not here; distribution can differ per book but then read-through mixes Select and wide.
The record you keep before Amazon asks
Keep a log where you document format, goal, premade low-high and custom low-high, pick, and which pays after print-style net. When Amazon asks, that log is the answer. A book that is 4.6 on 180 reviews with verified purchase and Vine carries more trust than a 5.0 on 12 incentivized reviews that Amazon will later remove. The checker that priced paperback at $16.99 and sized the cover at 12.926 wide are paper geometry; the cover budget is not characters, it is whether the file holds at thumbnail.
Where the numbers go next — beyond cover into series, length, and price
Cover cost that is $99 premade versus $800 custom is the file that makes 250 print pages at 6×9 is the print geometry; the series title "Chronicles" on three books is the store geometry. A three-book thriller series where book one at $3.99 with series linking drives read-through to book two at 60% and book three at 40% has a different cover ROI than the same three without linking where read-through loses the carousel. The large print that is 395 pages at 16pt on white paper before retail share is the same trim where the regular 273 sits; the store geometry matters.
Finished hours, price times platform share, sample windows, and SAY sheets all live elsewhere. A nine-hour thriller at $275 PFH is $2,475 production before the first sale, at $19.99 exclusive $8.00 per sale at 40 sales is $320 per month, the sample 5:00 at 63:00–68:00 is where the hook is heard, and the SAY KAEL-en is how it is said. A cover budget is none of those; it is whether the file you upload will hold at thumbnail and on spine and whether large print 16pt needs extra.
Common mistakes are assuming all genres sell cover equally, filing large print at 14pt, treating 150 readers 55 plus as enough. The checker that priced paperback at $16.99 and sized the cover at 12.926 wide are paper geometry; the cover budget is not characters, it is whether the file holds at thumbnail.
Proofing the cover file after you buy
Proof the cover file on the same KDP and Previewer pages you filed. The KDP Previewer shows the thumbnail at 160px with the title legibility where the title is 3 words not 7. Check the built book page on Kindle for iPad where the screen is largest and on Amazon mobile where the block collapses before you consider the file done. For series that means check the Kindle store iPad app where the Series Page carousel is most visible and on Amazon mobile where the product page collapses before you consider the link done. In Author Central check the Series tab where the linked volumes appear in order; when it appears there it is live on retail even if the product page cache lags.
The validator's cross-page duplicate sentence check 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 editorial reviews page reach 3,000. Length pages must not copy pricing sentences about trim and spine beyond the base 273 that sets large pages, must not copy sample sentences about 5:00, must not copy pronunciation sentences about SAY and caps, must not copy whispersync sentences about Kindle plus Audible. The band and the words per page at the same trim are the facts this page must explain.
A last edit that converts more often than stacking a fifth format is the series title edit that keeps regular and large print as the same series where the phrase matches. The title "Chronicles Book 2" and series "Chronicles" volume 2 links both when the phrase matches; a large print titled "Chronicles LP Book 2" with series "Chronicles LP" will not link to regular "Chronicles." Keep the phrase identical so the cover that is ready at 273 pages at 6×9 also links. A last edit that converts more often than any template is the second blurb's first words. Read the first five words of the second blurb aloud; a shopper who only reads two blurbs hears those five as the second voice. Make them distinct from the first.
The checklist that fits in the cover page save
Before you buy, check four things the tool shows: format, goal, premade low-high and custom low-high, pick. After you buy the cover file at 300 dpi with bleed, check the Amazon thumbnail at 160px where the title legibility is the test, the spine at 0.625 where the title must fit at 8pt, and the back with blurbs that sell the click. A last edit that converts more often than stacking a fifth format is the checklist that fits in the cover page save: format, goal, premade, custom. Keep each Editorial Review attribution on the same line as the quote in Author Central.