KDP cover size & spine width calculator
Enter your trim size, page count and paper to get your exact spine width and full-wrap cover size for Amazon KDP, then download a cover template.
Put the template on a layer under your artwork, then hide it before you export. KDP wants a single PDF with no template lines or guides left in it.
How KDP calculates your cover size
A paperback cover is one image that wraps around the book: back cover, spine, then front cover, with 0.125″ (3.2 mm) of bleed on every side that gets trimmed off. KDP's formula is:
| Cover width | bleed + back cover + spine + front cover + bleed |
|---|---|
| Cover height | bleed + trim height + bleed |
| Spine width | page count × paper thickness |
Spine width per page
| Ink and paper | Per page | 200 pages | 400 pages |
|---|---|---|---|
| Black ink, white paper | 0.002252″ | 0.450″ | 0.901″ |
| Black ink, cream paper | 0.0025″ | 0.500″ | 1.000″ |
| Standard color, white paper | 0.002252″ | 0.450″ | 0.901″ |
| Premium color, white paper | 0.002347″ | 0.469″ | 0.939″ |
Cream paper is a little thicker, so the same book has a wider spine on cream than on white. Change the paper and your cover changes too.
Text on the spine
KDP only allows spine text on books with more than 79 pages. Below that, the spine is too thin to print text reliably. Keep spine text at least 0.0625″ (1.6 mm) from each spine edge, because the fold can shift slightly. On the front and back, keep text at least 0.125″ inside the trim lines; many designers use 0.25″ to be safe.
The barcode
If you don't add your own, KDP prints the ISBN barcode in a white box 2″ wide and 1.2″ high near the bottom-right corner of the back cover. Keep that area clear of important text and art. The box on the template shows the usual position.
Numbers checked against KDP's help pages “Create a paperback cover” and “Paperback submission guidelines” on November 13, 2026. KDP's own cover calculator is the final word. Check it before you order proofs.
Writing in Google Docs?
Pressetter typesets your Google Doc into a KDP-ready paperback PDF and a Kindle eBook, then tells you your exact page count, spine width and cover size. The check and a full watermarked preview are free.
Questions
How wide is the spine of a 300-page paperback on KDP?
On white paper it's 300 × 0.002252″ = 0.676″ (17.2 mm). On cream paper it's 300 × 0.0025″ = 0.75″ (19.1 mm). Premium color paper is 300 × 0.002347″ = 0.704″.
What size should my KDP cover image be?
For a 6″ × 9″ paperback, the full cover is 12.25″ plus the spine width, by 9.25″ tall. At 300 DPI that's 3675 pixels plus the spine in pixels, by 2775 pixels. Use the calculator for your exact trim size and page count.
Can I put text on the spine?
Only if your book has more than 79 pages. Keep spine text at least 0.0625″ from each spine edge.
Why did KDP reject my cover size?
The most common reason is that the page count changed after the cover was made, so the spine width no longer matches. The second is choosing a different paper (cream is thicker than white). Recalculate with your final page count and paper.