KDP cover size requirements, explained

KDP rejects more covers for size problems than for anything else. The frustrating part is that none of the rules are hard — they’re just scattered across help pages and expressed in three different units. This post puts all of them in one place, with worked numbers you can check against your own book.

One file, three panels

The first thing to internalize: a paperback cover is one PDF page, not a front image. It contains, left to right:

1. The back cover
2. The spine
3. The front cover

The sheet gets wrapped around the printed book block, which is why the back cover is on the left — when you fold the sheet, the left side lands behind. If you’ve only ever made ebook covers, this is the mental shift: you’re designing a flat object that becomes three surfaces.

The size formula

Your file’s dimensions come from three inputs — trim size, page count and paper type:

width = 2 × trim width + spine width + 0.25 in height = trim height + 0.25 in

where spine width = page count × 0.002252 in (white paper) or × 0.0025 in (cream), and the extra 0.25 in on each dimension is bleed — 0.125 in on each outside edge.

Worked example — a 6 × 9 in novel, 300 pages, white paper:

• Spine: 300 × 0.002252 = 0.6756 in
• Width: 2 × 6 + 0.6756 + 0.25 = 12.9256 in
• Height: 9 + 0.25 = 9.25 in

Switch the same book to cream paper and the spine grows to 0.75 in, making the file exactly 13 × 9.25 in. Same book, same design, different file — which is why templates aren’t transferable between books, or even between paper choices.

Bleed: why your file is bigger than your book

Industrial cutters are accurate to roughly a millimetre, not to a hair. So KDP requires 0.125 in of bleed: your artwork must extend that far past the final trimmed edge on every outside edge of the wrap. After printing, the cutter slices through the bleed zone and whatever is in it is discarded.

Two practical consequences:

• Backgrounds, textures and full-bleed images must run all the way to the file edge. If they stop at the trim line, a slight cut drift leaves a white sliver on your cover.
• Nothing you care about should sit in the bleed zone, because it may not survive.

Note there’s no bleed between panels — the transitions from back to spine to front are folds, not cuts.

The safe zone: where text is allowed to live

The mirror image of bleed is the safe zone: KDP wants text and critical content at least 0.25 in inside the trim line. The cut can drift either direction, so a title hugging the edge on screen can end up uncomfortably close to it — or partially missing — on paper.

On the spine the clearance is horizontal: spine text must stay 0.0625 in away from each fold, and KDP only prints spine text at all on books of 79 pages or more.

The barcode zone

KDP prints its own ISBN barcode on every paperback, in a fixed spot: a 2 × 1.2 in area at the bottom-right of the back cover, inset 0.25 in from the trim edges. Anything you place there gets covered by a white barcode label. Plan your back-cover layout so the blurb ends above it — or use a tool that reserves the zone automatically.

Pixels and DPI

KDP recommends 300 DPI for cover files. Converting is one multiplication: inches × 300.

Our 6 × 9, 300-page, white-paper example — 12.9256 × 9.25 in — becomes 3,878 × 2,775 pixels. If you’re building the cover as a flat image in Photoshop or Canva, create the canvas at exactly those pixel dimensions and export without resampling.

DPI also constrains your source images. To keep a 6 × 9 front cover sharp, the front panel including bleed (6.125 × 9.25 in) needs 1,838 × 2,775 px minimum. A typical 1600 × 2560 ebook cover lands around 261 effective DPI at that size — usually acceptable in print, but below KDP’s recommendation, and worth knowing before you’re surprised by a quality warning.

The checklist

Before uploading, verify:

1. File width = 2 × trim width + spine + 0.25 in — to four decimal places, not “roughly”
2. File height = trim height + 0.25 in
3. Background art reaches every file edge (bleed covered)
4. Text is 0.25 in inside trim lines; spine text 0.0625 in clear of folds
5. Bottom-right 2 × 1.2 in of the back cover is clear for the barcode
6. Export at 300 DPI, ideally as PDF

Or let the math do itself

Every number above came out of the same formulas our free tools run. The cover size calculator gives you exact dimensions for any trim, page count and paper in inches, millimetres and pixels. And the free cover creator goes one step further: upload your ebook cover, enter your specs, and download a 300-DPI full-wrap PDF that passes all six checks by construction — free, no signup, entirely in your browser.