How do you export a print-ready PDF for Amazon KDP?

A print-ready KDP book is two separate PDFs: an interior at trim size plus bleed with correct gutter margins, and a cover wrap containing back cover, spine and front cover on one sheet. Both need 300 DPI images and embedded fonts. Most first-upload rejections come from one of four things, and all four are checkable before you upload.

What does the interior file need?

Page size = trim + bleed. If any art runs to the edge, every page is 0.125 in larger on each outer edge. An 8.5 × 8.5 book becomes an 8.75 × 8.75 document. Art must actually extend into that bleed area — stopping at the trim line leaves a white sliver when the cut drifts.

Mirrored margins. The inner (gutter) margin alternates sides between left- and right-hand pages, and needs more room than the outer margins because the binding swallows some of it. Minimum gutter is 0.375 in up to 150 pages.

Even page count, 24 minimum.

Embedded fonts. Every font must be embedded or the printer substitutes one, silently changing your layout.

300 DPI images. Covered below, because this is the one AI-illustrated books fail.

What does the cover file need?

One flat sheet, not three files:

width  = 0.125 + trim width + spine + trim width + 0.125
height = 0.125 + trim height + 0.125

Spine width is page count × paper caliper — 0.002347 in for colour. The spine calculation covers this in full.

Two constraints people miss: spine text needs 100+ pages, so most picture books cannot have any; and the barcode area is 2 × 1.2 in at the bottom-right of the back cover, which will be printed over.

Why does 300 DPI matter so much here?

Because it is where AI-illustrated books fail, and it is arithmetic rather than judgement.

An 8.75 in wide page at 300 DPI needs 2,625 pixels. Image models produce 1,024–1,536 px on the long edge, which is about 117 DPI across that page — under half of what print requires.

On screen this looks perfect. Printed, it is soft, and KDP's previewer flags low-resolution images at upload.

Resampling to print dimensions clears the check and removes the visible pixel grid. Be clear-eyed about what it does: it cannot add detail that was never generated. It makes a book print acceptably rather than beautifully. Pageling resamples every page and cover to the print target automatically on export.

What are the four common rejections?

Low-resolution images. The one above.

Content in the margins. Text or important art too close to the trim or in the gutter. The previewer shows margin overlays — use them.

Wrong cover dimensions. Almost always a wrong page count feeding the spine. Counting spreads instead of printed pages halves the spine and shifts the whole cover.

Missing bleed. Art that stops at the trim line on a full-bleed design.

How do you check before uploading?

Measure the exported PDF. Open it and check the page dimensions against your own calculation. They should agree to three decimal places. The interior should be trim + 0.25 in on each axis if you are using bleed; the cover should match the wrap formula.

Use KDP's previewer properly. Do not click through it. Look at the gutter on a spread near the middle of the book, look at the spine edges on the cover, and read any warnings rather than dismissing them.

Order a proof copy. Five dollars and a few days, and it catches everything the screen hides — colour printing darker than expected, resolution, margins that are legal but feel tight.

Frequently asked questions

Can I upload a Word document instead of a PDF? KDP accepts some other formats, but PDF is the only one where what you see is what prints. For an illustrated book, use PDF.

Do I need bleed if my illustrations do not reach the edge? No. Bleed is only for art running to the page edge. Full-page picture-book illustration almost always does.

Should the interior be RGB or CMYK? KDP accepts RGB and converts it. Expect print to look slightly darker and less saturated than your screen — another reason to order a proof.

Does the cover file include the interior? No. Two separate uploads: one interior PDF and one cover PDF.

What if my page count changes after making the cover? The cover must be rebuilt. Spine width derives from page count, so the whole file's dimensions change. Finalise the interior first.