Book Spine Width Calculator

Enter your page count and paper type for the exact KDP spine width.

Spine width
0.563"
14.3 mm · 169 px at 300 DPI

Need the whole cover, not just the spine? The Full-Wrap Cover Generator takes your front image plus these numbers and outputs a print-ready PDF with the spine, back cover, bleed, and barcode zone already laid out.

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Frequently asked questions

How do I calculate book spine width?+

Multiply your page count by the paper thickness per page. On Amazon KDP that caliper is 0.002252" for white paper, 0.0025" for cream, and 0.002347" for premium color. For example, 250 pages on white paper = 250 × 0.002252 = about 0.56".

Does spine width use page count or sheet count?+

Page count — every printed side counts as a page, so a 300-page book has 150 sheets but you use 300 in the formula.

How many pages do I need for text on the spine?+

KDP requires at least 79–100 pages before it will allow text on the spine, because a thinner spine cannot fit legible type without risking wrap onto the front or back cover.