Free KDP tool · no account
KDP Spine Width Calculator
Spine width on Amazon KDP depends on your page count and the paper you print on. Enter both and get the exact spine width, plus whether KDP lets you put text on it.
Spine width
0.45 in
11.44 mm
Per page
0.002252 in
Paper thickness used
Spine text
Allowed
Keep text within 0.325 in
Want the whole book, not just the numbers?
Describe a book in one sentence and kdpbook.us writes, illustrates and lays it out, then exports the KDP-ready interior and cover. Start with 2,000 free credits, no card.
Frequently asked questions
How does KDP calculate spine width?
KDP multiplies the page count by a per-page thickness that depends on the paper: for example 0.002252 in per page for black & white on white paper and 0.0025 in for cream paper. Hardcovers add a fixed amount for the boards.
Can I put text on my spine?
KDP only allows spine text on books with 79 pages or more, and the text must stay inside the spine with a safety margin. Under 79 pages the spine is too thin to print text on.
Why must the page count be even?
Books are printed in sheets, so KDP counts an odd page count as the next even number. This calculator rounds up the same way.
More free KDP tools
KDP Cover Size Calculator
Full-wrap cover size in inches, mm and pixels, plus a downloadable template.
KDP Printing Cost Calculator
Print cost per copy and the minimum list price KDP will accept.
KDP Royalty Calculator
Royalty per sale for print and Kindle at any list price.
KDP Trim Sizes
Every standard KDP trim drawn to scale, with page limits.
KDP Margins & Bleed Calculator
Gutter by page count, outside margins and page size with bleed.
KDP Rejection Decoder
Paste KDP's rejection email and see each issue with its fix.