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KDP Spine Width Calculator

Get exact spine width and full cover dimensions for your Amazon KDP book. Uses Amazon's official formulas for paperback and hardcover.

Book Details

Must be even. Min 24 pages.

Cover Dimensions

Spine Width

0.3978"

10.10 mm · 119 px @ 300 DPI

Full Cover Width

12.648"

3794 px

Full Cover Height

9.250"

2775 px

Bleed / Wrap

0.125" per side

Spine text is allowed at this page count.

How KDP Cover Layout Works

Back Cover

6"

Spine

0.398"

Front Cover

6"

Total: 12.648" × 9.250"

KDP Spine Width Formulas

Paperback

spine = (pages × paper_factor) + 0.06"
  • White paper: 0.002252" per page
  • Cream paper: 0.0025" per page
  • Color paper: 0.002252" per page

Hardcover (Case Laminate)

spine = (pages × 0.00226) + 0.187"
  • 0.187" accounts for board thickness
  • Paper type is always white for HC
  • Min 75 pages required

Frequently Asked Questions

Need a Complete Book Cover?

KDP Builder generates professional, spec-compliant covers with the correct spine width calculated automatically — plus manuscripts, interiors, and metadata.