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KDP Spine Width Calculator
The spine width and full-wrap cover size for a KDP paperback, from page count, paper and trim. Nothing is submitted or saved.
How it works
Spine width is the page count multiplied by the per-page thickness Amazon publishes for each paper type. The full cover adds the spine to twice the trim width plus bleed on both sides. Spine text is only allowed above a minimum page count. All three rules are taken from the KDP page linked below, read on the date shown.
Sources
Amazon KDP — Create a Paperback Cover · read 2026-09-11