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KDP spine width calculator
Enter your page count and paper to get the exact spine width of a KDP paperback, whether spine text is allowed, and how much room the text has.
How spine width is worked out
- Spine width = page count × thickness of one page.
- White paper and standard color:
0.002252in per page. Cream:0.0025in. Premium color:0.002347in. - Odd page counts are rounded up, because every sheet has two sides.
Spine text rules
- KDP prints spine text only on books with more than 79 pages.
- Leave at least 0.0625 in between the text and each edge of the spine, because the fold can move slightly when the book is bound.
- Thin spines leave very little room, so keep spine text short: title and author name.
Spine width by page count
Quick reference for the most common page counts.
| Pages | White, black ink | Cream, black ink | Standard color | Premium color |
|---|---|---|---|---|
| 24 pages | 0.054 in | 0.060 in | — | 0.056 in |
| 50 pages | 0.113 in | 0.125 in | — | 0.117 in |
| 80 pages | 0.180 in | 0.200 in | 0.180 in | 0.188 in |
| 100 pages | 0.225 in | 0.250 in | 0.225 in | 0.235 in |
| 150 pages | 0.338 in | 0.375 in | 0.338 in | 0.352 in |
| 200 pages | 0.450 in | 0.500 in | 0.450 in | 0.469 in |
| 300 pages | 0.676 in | 0.750 in | 0.676 in | 0.704 in |
| 400 pages | 0.901 in | 1.000 in | 0.901 in | 0.939 in |
| 500 pages | 1.126 in | 1.250 in | 1.126 in | 1.173 in |
| 600 pages | 1.351 in | 1.500 in | 1.351 in | 1.408 in |
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Start free with BookhatchChecked against KDP's help pages on 6 November 2026. KDP changes its rules from time to time, so confirm anything important on KDP's own pages before you publish. Bookhatch is not affiliated with Amazon.
Common questions
How do I calculate spine width for KDP?
Multiply the page count by the thickness of one page: 0.002252 in for white paper, 0.0025 in for cream and 0.002347 in for premium color.
When can a KDP book have spine text?
When it has more than 79 pages. The text must stay at least 0.0625 in from each edge of the spine.
Why is cream paper's spine wider?
Cream paper is slightly thicker per page, so the same number of pages makes a wider spine.
Does the trim size change the spine width?
No. Spine width depends only on page count and paper. Trim size changes the overall cover size.
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