Free KDP cover calculator
Publishing glossary
Spine width: how thick your paperback will be.
Spine width is the cover's spine panel thickness, calculated from page count and paper type.
Checked:
✓Formula: page count times paper factor✓White paper: 0.002252 inches per page✓Cream paper: 0.0025 inches per page
The KDP spine formula
KDP multiplies the final page count by a paper factor. The result sets the spine panel in the full-wrap cover, so the cover must be rebuilt when pagination changes.
- Recalculate after every pagination change
- No spine text under 80 pages
- Premium color uses 0.002347 per page
Calculating it exactly
The cover calculator turns page count and paper into the full wrap including spine and bleed, removing the most common cover rejection cause.
FAQ
Frequently asked questions
How does KDP calculate spine width?
Final page count times a paper factor: 0.002252 for white, 0.0025 for cream, 0.002347 for premium color paper.
What happens if my spine width is wrong?
The cover is rejected or printed with a shifted spine, so the book cannot be listed until the file is fixed.
Put the definition to work for free.
Run your manuscript through the matching free check and see how the term applies to your own book.