Already have a finished full-wrap PDF? Drop it in and find out what book it is actually a cover for, before Amazon tells you. Nothing is uploaded — the file is measured in your own browser.
or drop it here. Up to 96 MB. It is read in this tab — there is no upload on this page.
Which book the page size fits, the spine it implies, and how that compares with the book you are publishing — plus the artwork resolution, the fonts, and whether it is the single page a KDP cover has to be. Every row is measured from your file. Where something cannot be determined honestly, it says so instead of showing a tick.
A KDP paperback wrap is one page whose size is entirely determined by three things: the trim, the final page count and the paper. Back cover plus spine plus front cover across, trim height down, and 0.125" of bleed added on every outside edge. Nothing in the PDF records which of those three you chose — the file is just a rectangle of a particular size, and Amazon compares that rectangle against the book you set up in KDP.
Which means the rectangle can be run backwards. Take the height, subtract the bleed, and you have the trim height. Take the width, subtract the bleed and two trim widths, and what is left is the spine. Divide the spine by the caliper of each paper Amazon offers and you get the page count that spine was built for. This page does that against all 16 standard KDP paperback trims, so instead of "your dimensions are wrong" you get "this is a 6 × 9 wrap for about 300 pages on white paper" — and if that is not the book you are publishing, you have just found the actual problem.
Everything else it reports is measured from the same file: whether it is one page, whether the page is rotated, how many pixels your artwork has over the inches it must cover, and whether the fonts travel with the file or merely get named. Where something cannot be determined honestly it says so rather than showing a tick. Amazon's rules behind all of it were last checked against their published help pages on 2026-08-27.
And what it cannot tell you
No. The file is read by your browser and measured there — there is no upload step on this page, no account, and nothing about your cover is sent to us or stored by us. Closing the tab is all it takes to be rid of it.
Leave them blank. The checker works out which books the page size fits and tells you, which is the whole reason to arrive with a mystery PDF. Filling them in adds one thing: a direct comparison against the book you believe you are publishing, and a warning when the file disagrees.
Because it genuinely does. The spine width is fixed by the page, but the page count that produces that spine depends on the paper: a 0.676" spine is about 300 pages on white, 288 on groundwood or premium colour, and 270 on cream. The trim you are publishing at decides which line applies — the file cannot say.
No, and nobody can offer you that. It measures what is measurable in the file — page size, spine against page count, resolution, fonts, structure — against Amazon's published specifications, last checked on 2026-08-27. It says nothing about your interior, your metadata, your categories or what a human reviewer makes of your cover art. Amazon retains final review. Look at the file in KDP's Print Previewer and order a proof before you launch.
Because it cannot do so honestly. Knowing whether your artwork reaches the bleed means knowing where every mark on the page falls, which needs the file rendered rather than read. A green tick we could not stand behind is worse than no tick, so those two are absent rather than guessed.
Some design tools nest artwork inside a reusable object with its own internal coordinates. This checker follows images painted directly onto the page and does not open those nested objects, so their print resolution is unknown rather than fine. Everything else on the file is still measured.
Up to 96 MB. Past that a browser cannot safely hold the file and the objects needed to parse it, so it is refused before anything is read rather than crashing the tab.
Read the "what book this file fits" row first — it often turns out the file is correct and the page count changed, or the trim in KDP is not the one the cover was built at. If the cover artwork itself is fine and only the wrap is wrong, the Paperback Wrap Builder rebuilds the wrap around your front cover at the right size, free.