About kdpcover.pro
kdpcover.pro is an independent precision calculator for Amazon KDP paperback and case-laminate hardcover covers. The KDP white-paper paperback spine width formula is 0.002252 inches per page; cream is 0.0025; standard color is 0.002252; premium color and case-laminate hardcover are both 0.002347. Multiply your interior page count by the right multiplier and you have the spine width.
Methodology
Every multiplier is verified against KDP’s official cover-template generator. All math runs in your browser; nothing is uploaded. The full set of formulas lives in lib/kdp/calc.ts with full unit-test coverage.
Authoritative sources
- KDP Paperback Cover Creation
- KDP Hardcover Cover Creation
- KDP Trim Size, Bleed & Margins
- KDP Barcode Requirements
- KDP Print Options
- KDP Cover Calculator (template generator)
FAQ
- What is the KDP white-paper paperback spine width formula?
- The KDP white-paper paperback spine width formula is 0.002252 inches per page. Multiply your interior page count by 0.002252 to get the spine width in inches.
- What is the spine multiplier for cream paperback?
- 0.0025 inches per page. Cream pages are slightly thicker than white, so a 300-page cream paperback has a 0.75″ spine versus 0.6756″ for white.
- Does KDP hardcover use a different multiplier than paperback?
- Yes. Case-laminate hardcover always uses 0.002347 inches per page regardless of paper choice, and adds 0.4″ hinge each side of the spine plus 0.51″ wrap on the outside edges.
- What's the difference between paperback and hardcover bleed?
- Paperback bleed is 0.125″ on every outside edge. Hardcover does not use traditional bleed; instead it has a 0.51″ wrap that folds inside the case.
- What is the minimum page count for spine text on a KDP cover?
- 79 pages. Below 79 pages, the spine is too narrow for KDP's automated review to accept printed text or graphics.
- What is the KDP barcode size and placement?
- The recommended barcode area is 2″ × 1.2″ in the bottom-right of the back cover, with at least 0.25″ clearance from the spine and trim edges and 0.76″ from the bottom. The minimum acceptable size is 1.4″ × 0.8″.
- What page-count range does KDP allow?
- KDP paperback supports 24–828 pages. Case-laminate hardcover supports 75–550 pages. Maximums are also subject to trim-size-specific limits.
- What file format does KDP require for cover upload?
- A single flattened PDF combining back cover, spine, and front cover, with fonts embedded, no crop marks, 300 DPI minimum, CMYK preferred. Files should be 40 MB or less; 650 MB is the hard limit.
Contact
Bugs, feature requests, or accuracy reports: hello@kdpcover.pro.