KDP Spine Width Calculator
Spine width for any page count on white, cream or color paper, in inches, millimetres and pixels.
Spine width chart
| Pages | Black & white / white paper | Black & white / cream paper | Standard color / white paper | Premium color / white paper |
|---|---|---|---|---|
| 24 | 0.054 in | 0.060 in | 0.054 in | 0.056 in |
| 50 | 0.113 in | 0.125 in | 0.113 in | 0.117 in |
| 80 | 0.180 in | 0.200 in | 0.180 in | 0.188 in |
| 100 | 0.225 in | 0.250 in | 0.225 in | 0.235 in |
| 150 | 0.338 in | 0.375 in | 0.338 in | 0.352 in |
| 200 | 0.450 in | 0.500 in | 0.450 in | 0.469 in |
| 250 | 0.563 in | 0.625 in | 0.563 in | 0.587 in |
| 300 | 0.676 in | 0.750 in | 0.676 in | 0.704 in |
| 400 | 0.901 in | 1.000 in | 0.901 in | 0.939 in |
| 500 | 1.126 in | 1.250 in | 1.126 in | 1.173 in |
| 600 | 1.351 in | 1.500 in | 1.351 in | 1.408 in |
| 700 | 1.576 in | 1.750 in | 1.576 in | 1.643 in |
| 800 | 1.802 in | 2.000 in | 1.802 in | 1.878 in |
Specs last checked against KDP's published specs in September 2026.
Frequently asked questions
How is KDP spine width calculated?
Spine width = page count × paper thickness. KDP uses 0.002252 in per page for white paper and standard color, 0.0025 in for cream paper, and 0.002347 in for premium color.
How many pages do I need for spine text?
KDP allows spine text on paperbacks with 80 pages or more. Leave at least 0.0625 in between the text and each spine edge.
Does trim size change spine width?
No. Spine width only depends on page count and paper type. Trim size changes the front and back cover size.