Book cover dimensions and spine width
The three panels and the bleed
Reading left to right, a cover PDF is: bleed, back cover, spine, front cover, bleed. The bleed is also added at the top and bottom. KDP and IngramSpark both use 0.125 in of bleed. The back and front panels are each the trim size. So:
Width = 0.125 + trim width + spine + trim width + 0.125
Height = 0.125 + trim height + 0.125
Everything that matters, text and faces, stays at least 0.125 in inside the trim line (KDP) or 0.5 in (IngramSpark's recommendation). Backgrounds and artwork run all the way out into the bleed.
The spine
The spine is the page count times the thickness of one leaf. Every page count is rounded up to an even number, since a sheet has two sides. KDP publishes its paper thicknesses:
| KDP paper | Per page | 100 pages | 200 pages | 300 pages | 400 pages |
|---|---|---|---|---|---|
| White, black & white | 0.002252 in | 0.225 | 0.450 | 0.676 | 0.901 |
| Cream, black & white | 0.0025 in | 0.25 | 0.5 | 0.75 | 1.0 |
| Standard color | 0.002252 in | 0.225 | 0.450 | 0.676 | 0.901 |
| Premium color | 0.002347 in | 0.235 | 0.469 | 0.704 | 0.939 |
IngramSpark's paper is different (50 lb white or creme, 70 lb white for color) and it does not publish a per-page figure. Its cover template generator, in the account dashboard, emails a template with the exact spine for your title. Use it. A cover made to KDP's spine will be slightly off on an IngramSpark copy.
A worked paperback example
A 6 × 9 novel, 312 pages, cream paper, for KDP.
- Spine: 312 × 0.0025 = 0.78 in
- Width: 0.125 + 6 + 0.78 + 6 + 0.125 = 13.03 in
- Height: 9 + 0.25 = 9.25 in
- Front cover trim area: from x = 6.905 to x = 12.905; safe text area from 7.03 to 12.78
- Barcode: lower right of the back cover, a 2 × 1.2 in white box at least 0.25 in from the trim. KDP places one for you if you leave the area clear.
Hardcover (case laminate)
A KDP hardcover cover is not a paperback cover with a thicker spine. The printed sheet wraps around rigid boards, so every dimension changes:
- The wrap replaces the bleed: 0.591 in (15 mm) on all four outer edges, folded around the boards.
- The boards are larger than the trim: 0.197 in wider and 0.236 in taller than the page.
- The spine is the page thickness plus 0.189 in for the boards and the cloth, using the same per-page figures as the paperback.
- A hinge of 0.394 in on each side of the spine is a groove; keep text out of it.
- Page count: 75 to 550. Available in 5.5 × 8.5, 6 × 9, 6.14 × 9.21, 7 × 10 and 8.25 × 11.
The same 6 × 9 novel at 312 pages on cream paper as a hardcover: spine 312 × 0.0025 + 0.189 = 0.969 in; each board 6.197 × 9.236 in; full sheet 0.591 + 6.197 + 0.969 + 6.197 + 0.591 = 14.545 in wide and 9.236 + 1.182 = 10.418 in tall. KDP's cover calculator produces the same figures and a template with the guides drawn on.
The ebook cover
The ebook cover is only the front panel, as a JPEG. KDP recommends 2,560 × 1,600 pixels (1.6 to 1) with at least 1,000 pixels on the short side; Apple Books wants at least 1,400 on the short side. Export it from the same design as the front cover. It should read at thumbnail size, which means the title has to be large and the image simple.
Practical order of work
- Finish the interior. Every edit changes the page count.
- Fix the trim size and the paper.
- Read the final page count from the PDF.
- Calculate the spine, or download the printer's template for that page count.
- Build the cover on the template. Delete the template layer before export.
- Export at 300 dpi, fonts embedded, no marks, as a single PDF. Check the page size matches the template.
- Order a proof and check the spine alignment in the hand.
Questions
How do I calculate the spine width of my book?
Multiply the page count by the thickness of one sheet of the paper. For KDP: white paper 0.002252 in per page, cream 0.0025 in, premium color 0.002347 in. A 300-page book on cream paper has a 0.75 in spine. IngramSpark uses its own paper and gives you the spine on its cover template.
What size is a 6×9 paperback cover?
Width = 0.125 bleed + 6 back + spine + 6 front + 0.125 bleed. Height = 9 + 0.25 = 9.25 in. For a 300-page book on cream paper the spine is 0.75 in, so the cover PDF is 13 × 9.25 in.
Can I put the title on the spine?
On KDP, only if the book has more than 79 pages. Keep spine text at least 0.0625 in from the spine edges, and expect the fold to vary by up to that much, so avoid designs that depend on a hard line at the spine edge.
What happens if my page count changes after the cover is made?
The spine width changes, and the cover no longer fits. Ten pages on cream paper is 0.025 in, enough to push the spine text onto the front cover. Make the cover last, or re-export it whenever the page count changes.