CoverRescue

KDP Spine Width Calculator

Turn final page count and paper stock into the exact paperback spine width.

Private, local check

KDP paperback setup

Enter the final paperback production settings.

Finished front-cover width and height.

Use the page count shown after KDP processes the interior file.

Paper thickness determines the spine coefficient.

Paperback formula: two trim widths + spine + 0.125 in bleed on both outer edges; trim height + 0.25 in total bleed.

Your result

Your KDP cover dimensions

Full cover13.050 × 9.250 in331.5 × 235 mm
Spine width0.8000 in20.3 mm
Pixel size3915 × 2775300 DPI
This page count is above 79 pages, so KDP can print spine text. Keep text at least 0.0625 in from each spine edge.

KDP paperback spine coefficients

Black-and-white white paper uses 0.002252 inch per page, cream paper 0.0025 inch, groundwood 0.00235 inch, and color paper 0.002347 inch. The calculator multiplies the selected coefficient by the even page count.

When can a KDP spine include text?

KDP only prints spine text on books with more than 79 pages. When text is allowed, keep at least 0.0625 inch between the text and each spine edge to accommodate binding variance.