KDP spine width & cover size calculator

Enter your trim size, page count and paper type. The spine uses Amazon's published per-page thickness for paperback stock (white 0.002252 in/page, cream 0.0025 in/page). Full cover size includes the standard 0.125 in bleed on every outer edge.

Trim size (inches)Page count (paperback minimum 24)Paper type

Formulas: spine = page count × per-page thickness. Full cover width = 0.125 (bleed) + trim width (back) + spine + trim width (front) + 0.125 (bleed). Full cover height = trim height + 0.25 (bleed top and bottom). Interior pages with bleed: width = trim width + 0.125, height = trim height + 0.25. Multipliers and rules last checked against KDP's published cover specifications on 2026-11-09. Always confirm with the template KDP generates in your own account before going to print.