Calculate the exact spine width for your Amazon KDP paperback. The spine width determines how wide the spine area of your cover needs to be, and it varies based on your page count and paper type.
Spine Width Formula
Amazon KDP uses two different paper stocks with different thicknesses:
| Paper Type | Thickness Per Page | Best For |
|---|---|---|
| White paper | 0.002252" (0.0572 mm) | Non-fiction, textbooks, books with images |
| Cream paper | 0.0025" (0.0635 mm) | Fiction, memoirs, poetry, literary works |
Formula: Spine Width = Page Count × Paper Thickness Per Page
For example, a 300-page book on cream paper: 300 × 0.0025" = 0.75" (19.05 mm)
Quick Reference Table
| Pages | White Paper Spine | Cream Paper Spine |
|---|---|---|
| 100 | 0.225" (5.7 mm) | 0.250" (6.4 mm) |
| 150 | 0.338" (8.6 mm) | 0.375" (9.5 mm) |
| 200 | 0.450" (11.4 mm) | 0.500" (12.7 mm) |
| 250 | 0.563" (14.3 mm) | 0.625" (15.9 mm) |
| 300 | 0.676" (17.2 mm) | 0.750" (19.1 mm) |
| 350 | 0.788" (20.0 mm) | 0.875" (22.2 mm) |
| 400 | 0.901" (22.9 mm) | 1.000" (25.4 mm) |
| 500 | 1.126" (28.6 mm) | 1.250" (31.8 mm) |
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