PrecisionKit

KDP Cover Calculator

Plan full wraparound paperback cover and spine dimensions from trim size and page count — not an official Amazon KDP tool, and not a guarantee of acceptance.

Trim size preset

Interior page count, not including the cover.

Enter trim size and page count to calculate the full wraparound cover size.

Supported binding and paper combinations

This tool currently supports paperback only, with white, cream, standard color and premium color interior paper. Hardcover uses a different board, hinge and wrap structure and is intentionally blocked until that geometry is sourced and verified — selecting it will show an error rather than a wrong number.

Spine and full-wrap methodology

How this is calculated
spine (in) = pageCount × per-page thickness | wrapW = 2×trimW + spine + 2×0.125 | wrapH = trimH + 2×0.125

Spine width is estimated from page count using Amazon's own published per-page thickness figures. The 0.125 in outer bleed is fixed by KDP's own requirement and is not user-editable here.

Worked example

6 × 9 in trim, 200 pages on cream paper: spine = 200 × 0.0025 in = 0.5 in. Full wrap width = 2 × 6 + 0.5 + 2 × 0.125 = 12.75 in; height = 9 + 2 × 0.125 = 9.25 in.

Cover diagram and safe areas

The full wrap is back cover, spine and front cover side by side, each with the fixed bleed on its outer edge only — never between panels. Keep text and important artwork well clear of the spine fold and the trim edges.

Official template verification

This is a planning estimate, not an Amazon KDP tool and not affiliated with or endorsed by Amazon. Always generate and check your final cover against KDP's own cover calculator and template at upload time — spine width in particular can shift slightly as printing specifications change.

Bleed
Fixed at 0.125 in per KDP's requirement — never zero, never user-editable.
Spine estimate
Calculated from page count, not looked up from a verified per-title source — always confirm before upload.

Questions

Does interior bleed change cover bleed?

No — they're independent settings. Interior (page) bleed affects whether images inside the book print to the edge of the page; cover bleed is the fixed 0.125 in KDP requires on every outer edge of the wraparound cover file, regardless of whether the interior uses bleed. Changing one does not change the other.

Can paperback formulas be used for hardcover?

No. Hardcover uses a different wrap structure — a rigid board, a hinge/gutter allowance next to the spine, and different bleed and margin rules than a paperback's simple flat wraparound. This tool intentionally does not apply the paperback formula to hardcover; use it for paperback planning only until hardcover-specific geometry is sourced and verified.

Sources