What KDP checks on a cover
- The full size: bleed + back cover + spine + front cover + bleed, with 0.125 in of bleed on the top, bottom and outside edges (KDP Help, Create a Paperback Cover, checked September 28, 2026).
- A spine as wide as your page count and paper make it, so the cover matches the interior you upload.
- Spine text only on books with more than 79 pages, with at least 0.0625 in on each side of the text so it doesn’t wrap onto the front or back.
- A clear barcode area on the back cover (KDP Help, Barcodes, checked September 28, 2026).
Full wrap = 2 × trim + spine + bleed
The spine is the page count times the paper’s thickness per page: 0.0025 in per page on cream paper. Worked example for a 6 × 9 in paperback, 200 pages, black ink on cream paper:
| Part | Width |
|---|---|
| Bleed (outside of the back) | 0.125 in |
| Back cover (trim width) | 6 in |
| Spine (200 × 0.0025 in) | 0.5 in |
| Front cover (trim width) | 6 in |
| Bleed (outside of the front) | 0.125 in |
| Full cover width | 12.75 in |
| Full cover height (trim + 2 × bleed) | 9.25 in |
Change the page count and the spine and the width change with it. The free KDP cover size calculator gives the size for any trim, paper and page count, paperback or hardcover, with a downloadable template; the spine width calculator gives the spine alone.
Spine text
KDP prints text on the spine only when the book has more than 79 pages (KDP Help, Create a Paperback Cover, checked September 28, 2026). Page counts are even, so that means from 80 pages. kdpbook.io also checks that the spine is wide enough to hold readable text with 0.0625 in of space on each side, so on a paperback the title and author appear on the spine from:
| Paper | Spine text from |
|---|---|
| Black & white · white paper | 100 pages |
| Black & white · cream paper | 90 pages |
| Black & white · groundwood paper | 96 pages |
| Standard color · white paper | 100 pages |
| Premium color · white paper | 96 pages |
The barcode area
If you don’t add a barcode, KDP prints one on the back cover. Its suggested size is 2 × 1.2 in (50.8 × 30.5 mm), at least 0.25 in from the spine and the trim (KDP Help, Barcodes, checked September 28, 2026). kdpbook.io keeps that corner of the back cover free of text and important art.
The Kindle eBook cover
KDP’s ideal Kindle cover is 2,560 pixels high by 1,600 wide (a 1.6:1 ratio), in JPEG with RGB color (KDP Help, Kindle eBook Cover Guidelines, checked September 28, 2026). kdpbook.io exports that JPEG with the Kindle EPUB, from the same front cover as the print edition. Coloring, puzzle, activity, journal and notebook books are print only, so they get no Kindle cover.
How the cover is made in kdpbook.io
The cover is made inside a book project: you describe the book, or import your manuscript, and the cover is designed with it, because its size depends on the final page count. There is no cover-only mode.
- The front art is drawn in the book’s illustration style, with its main characters when the book has some.
- The title, subtitle and author are typeset over it with one of 5 cover templates, so the lettering stays sharp and correctly spelled.
- The back cover carries the blurb, and the spine the title and author once the book is thick enough.
- In the editor you can change the text, fonts, colors and template, or redraw the front art, and the wrap is re-sized when the page count changes.
KDP also has its own Cover Creator inside your KDP account. kdpbook.io is a separate, independent tool: you download the cover PDF and upload it in KDP with the interior. Only need the numbers? The cover size calculator and its template are free, with no account.