Free tool · Amazon KDP paperbacks
Book spine and cover size calculator
Enter your page count (or your word count) to get the spine width and the exact size of the full cover (back, spine and front, with bleed) that Amazon KDP needs.
Write the whole book with NovaTek
NovaTek's app writes the book with you and makes your KDP files, including the full cover with the spine sized for your page count.
Start freeQuestions
How is the spine width calculated?
Amazon KDP multiplies your page count by the thickness of one page: 0.002252 in for white paper with black ink, 0.0025 in for cream paper, 0.002252 in for standard color and 0.002347 in for premium color.
What size should my full cover be?
Cover width = 0.125 in bleed + back cover width + spine width + front cover width + 0.125 in bleed. Cover height = trim height + 0.25 in (bleed at top and bottom).
When can I put text on the spine?
KDP allows spine text only when the book has more than 79 pages. Thinner spines are too narrow for readable text.
How many words fit on a page?
It depends on the trim size, font and margins. As a rough guide, a 6 × 9 in novel holds about 250 to 300 words per page; this calculator uses an estimate, so check your final PDF.
Spine width per page and the cover formula come from Amazon KDP Help (checked November 2026). Always confirm with KDP's own cover calculator before ordering.
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