Keep the front cover you already have. Build the back and spine, check the KDP layout, and export one finished paperback PDF. Free, no account, and your cover never leaves your browser.
An ebook cover is one image: a front, usually 1600 × 2560 px, RGB, no bleed. A paperback is a single wrap — back, spine and front on one PDF page, with 0.125" of bleed on every outside edge that the printer cuts away. Drop the ebook file onto a paperback template and you get an empty back, an empty spine, and white edges where the trim landed.
The spine is the part that catches people out, because it is not a design decision. It is your final page count multiplied by the caliper of the paper you chose: a 300-page novel is 0.6756" on white and 0.75" on cream, and the whole wrap gets wider or narrower with it. Change the page count after formatting and every panel moves.
This page does that arithmetic from your real book, shows you exactly where the trim, bleed, text-safe and barcode areas fall, and refuses to quietly crop the cover you already like. Everything happens in your browser — nothing is uploaded, nothing is stored, and the export costs nothing.
These are the checks the builder performs on your wrap, live, as you edit — and the last two on the file after it has been written. They are our production checks, not an Amazon verdict: KDP’s Print Previewer and its reviewers decide whether a cover is accepted.
Back trim + spine + front trim, plus bleed on every outside edge, measured against the trim you chose.
Effective KDP pages × the caliper of your paper. Odd counts are rounded up, and you are told when they were.
Amazon's page window is per trim AND per paper — cream reaches 776 pages at 6 × 9 and stops at 550 at 8.5 × 8.5.
Your pixels over the inches they have to cover, at this trim and this fit. A number, not a verdict.
Whether the front panel is covered edge to edge, or whether the extended background will show beside it.
How much of the cover you added falls outside the printed panel — zero unless you chose to crop.
Every laid line measured against the text-safe inset, not just the column it was flowed into.
Whether Amazon prints on the spine at all at your page count. Reported as their rule, because it is.
What is left after the fold clearance, against 8 pt. A MakeMyBookCover recommendation, kept separate from Amazon’s.
The 2 × 1.2" reserve in the back cover's spine-side bottom corner, checked against every line of copy.
Every character is drawn as an outline, so there is no font in the file to be missing, substituted or wrongly subset.
Measured on the file that was actually produced, after it was written — not on what the renderer intended.
The exported page reopened and measured against the size this book needs, before the download is offered.
A JPG or PNG, read by your browser. You immediately see its pixel size, its shape against the paperback panel, and what print resolution it works out to at your trim.
Trim size, paper, and the final page count — read exactly out of your interior PDF if you have one to hand. The spine and the whole wrap are computed from those three.
Pick a back-cover layout and fill the blocks it uses: hook, description, review quote, bio, imprint. Add spine title and author when the spine is thick enough to carry them.
Trim, bleed, text-safe, spine-safe and the barcode reserve, all switchable on the canvas. None of them are drawn into the exported file.
One page at the exact physical size, artwork embedded rather than resampled, checked after it is written and downloaded straight to your machine. No account, no charge, no expiring link.
Not unless you ask for it. The default is Preserve, which keeps every pixel of the file you added — where your cover's shape does not match the paperback panel, the background is extended beside it rather than the artwork being cut. Fill covers the panel edge to edge and does crop; when you pick it, the canvas shows the cropped area faded out and preflight tells you what percentage of the image it is. Custom lets you place it yourself with zoom and position. There is no mode in which the tool crops without showing you.
Yes — the spine width is page count × paper caliper, so a draft number gives you a spine that is wrong by exactly the difference. Use the page count from your formatted interior PDF, not from your manuscript. Odd counts are rounded up because KDP prints in even sheets, and the builder shows you when that has happened.
You can point the builder at it, and it reads the page count exactly rather than making you count. The file is parsed in your browser using its page tree — nothing is uploaded, no text or images are extracted, and your manuscript never touches our servers. If the pages all measure the same and match a trim we render, the trim is set for you as a suggestion you can change.
You get the number, not a shrug. The builder shows the effective print resolution for your file at the trim and fit you chose — the same 1600 × 2560 cover is about 312 PPI on a 5 × 8 and about 277 PPI on a 6 × 9, because the pixels are being spread over more inches. Below 300 you get a warning naming the pixel dimensions that would fix it at that trim, and you can still build and export the wrap: a slightly soft print is your decision to make, not ours to block.
Change the number and the whole wrap reflows in front of you: the spine widens or narrows, the front and back panels move, the guides follow, and preflight re-runs. Nothing has to be rebuilt. Come back weeks later and this browser still remembers your settings — trim, page count, paper, layout, blurb, spine text, colours — so you change one field and export again. The one thing it does not remember is the artwork: your cover is never stored, here or anywhere, so you add the file again first. That is a deliberate trade, and it is why nothing of yours is sitting on a server.
Amazon prints its own barcode in a 2 × 1.2" area, 0.25" in from the bottom corner of the back cover on the spine side. The builder reserves that area, marks it on the canvas, keeps your back-cover copy out of it, and checks it is clear before you export. If you have your own barcode, the same area is kept clear for you — but placing your own barcode image is not supported yet, so you would add it to the exported PDF in your own editor.
No, and nobody can offer you that. Our checks cover what we can measure: wrap dimensions, spine against page count, bleed coverage, artwork resolution, text inside the safe areas, spine fit, and the barcode reserve. They say nothing about your interior file, your metadata, your categories, or what a human reviewer thinks of your cover art. Passing means the file's geometry is right. Always look at the exported PDF in KDP's Print Previewer and order a proof copy before you launch.
One PDF page at the exact physical size your book needs, carrying back, spine and front, with your artwork embedded as the original bytes rather than resampled, and no guides or crop marks. It is built in your browser, so it is free, needs no account, and there is no download link to expire — the file is on your machine the moment it is made. The colour space is sRGB, not CMYK; see the next answer.
No — there is no font in the file at all. KDP asks for embedded fonts because a cover that merely NAMES a typeface can be re-rendered in a substitute by whichever machine prints it, and your careful line breaks come back wrong. Every character on your wrap is drawn as a filled vector outline instead: no font program to subset, to licence, to go missing or to be swapped. That is the stronger version of the same guarantee. The faces are Cormorant Garamond with Cinzel headlines, or Source Sans 3 with Oswald headlines, all open-licensed. Preflight measures the exported file and will not report this as passing unless it is true of the bytes.
Because we would rather say so than pretend. KDP's print guidance recommends CMYK, and this builder outputs sRGB. In practice the visible risk is a colour shift — saturated colours can print differently from how they look on screen. The reliable check is a physical proof copy, ordered and looked at before you launch. If you do want a colour-managed conversion, treat the exported file as the finished production file it is: a conversion can rasterise the page or change its size, so run whatever comes out of it through KDP's Print Previewer again and confirm the page is still exactly the size your book needs. We are not going to recommend a specific tool for that, because we have not print-validated one.
We never receive it. The cover is read by your browser, the wrap is composed by your browser, and the PDF is written by your browser — there is no upload step on this page at all. Nothing about your cover, your interior PDF or your back-cover copy is sent to us or stored by us. What this browser keeps for you, in its own local storage, is your SETTINGS: trim, page count, paper, back-cover layout and copy, spine text, typeface, colours, barcode choice, and the name and pixel size of the file you used — so it can tell you which one to bring back. The image itself is never written there, in any form. Clearing your browser data clears the settings too.
Paperback only, and only at the 16 standard trims — but all 16 of them, including the square and landscape sizes. Hardcover is out because it has a different trim list and a different spine formula: a case spine is not page count × paper caliper, so nothing here would compute it correctly. Custom trims are out because Amazon publishes no per-page limit for a size it has no row for. For either, the Cover Size Calculator gives you a marked PDF, PNG or SVG template to lay the wrap out yourself in Affinity Publisher or InDesign.
You do not have to. Covers generated here live in a project, and that project's Publish workspace builds the wrap directly from whichever version you marked for downloads — no export-and-re-import round trip, and building, formatting and exporting the wrap uses 0 AI Generations there too. It is also the fuller path: a much longer blurb and a choice of four looks, each with its own back-cover composition and type pairing. The KDP maths — trim, page count, paper, spine width, bleed and the barcode reserve — is the same on both. Use this page when the front cover came from somewhere else.
Don’t have a front cover yet? Our AI cover generator makes the artwork — then bring it back here for the wrap.
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