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
0.3378"
8.58 mm · 101 px @ 300 DPI
Full Cover Width
12.588"
3776 px
Full Cover Height
9.250"
2775 px
Bleed / Wrap
0.125" per side
Spine is only 0.338" — needs ≥0.35" for text.
How KDP Cover Layout Works
Back Cover
6"
Spine
0.338"
Front Cover
6"
Total: 12.588" × 9.250"
KDP Spine Width Formulas
Paperback
spine = pages × paper_factor- White paper: 0.002252" per page
- Cream paper: 0.0025" per page
- Standard Color paper: 0.002252" per page
- Premium Color paper: 0.002347" 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
How is KDP spine width calculated?+−
For paperbacks, spine width = (page count × paper thickness per page) + 0.06 inches for the cover. White paper is 0.002252" per page, cream is 0.0025", and standard color is 0.002252". For hardcovers, the formula is (page count × 0.00226) + 0.187" for board thickness — no cover offset is added.
When can I add text to the spine?+−
Amazon KDP requires at least 79 pages before spine text is allowed. The spine must also be at least 0.35" wide. Below that, the spine must remain blank — any text or graphics will cause your cover to be rejected.
What trim sizes does KDP support?+−
KDP supports 17 paperback trim sizes ranging from 5"×8" to 8.5"×11". Hardcover (case laminate) supports 6 trim sizes: 5.5"×8.5", 6"×9", 6.14"×9.21", 6.69"×9.61", 7"×10", and 8.25"×11". The most popular sizes are 6"×9" and 5.5"×8.5".
What's the difference between white and cream paper?+−
White paper (0.002252" per page) produces a thinner spine and is standard for most books. Cream paper (0.0025" per page) is slightly thicker, giving the book a more substantial feel — popular for novels and literary fiction. Cream paper is only available with black-and-white ink.
Design a full wrap cover with the right spine
KDP Builder takes you from this free tool to a complete, upload-ready package — manuscript or interior, cover, and metadata.
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