The spine of a print book is nothing but page count × paper thickness. Amazon KDP publishes the thickness per page for each paper type, so the whole calculation fits in one line — and the table further down already contains the answer for most books.
The formula
Paperback: spine width = page count × thickness per page.
Hardcover: the same, plus 4.8 mm (0.189")
for the boards.
| Paper | Per page (inches) | Per page (mm) | Available for |
|---|---|---|---|
| White, black & white interior | 0.002252" | 0.0572 mm | paperback, hardcover |
| Standard colour | 0.002252" | 0.0572 mm | paperback only |
| Premium colour | 0.002347" | 0.0596 mm | paperback, hardcover |
| Cream | 0.0025" | 0.0635 mm | black & white only |
Which one applies to a cookbook? Almost always premium colour: food photographs on standard colour paper look noticeably flatter, and cream paper is not offered in colour at all. Premium colour is also the only colour paper available for hardcover.
Spine width table
Read off your page count — or take the row above and below it and interpolate; the relationship is strictly linear.
| Pages | B&W / standard colour | Premium colour | Cream (B&W only) |
|---|---|---|---|
| 24 | 0.054" (1.37 mm) | 0.056" (1.43 mm) | 0.060" (1.52 mm) |
| 50 | 0.113" (2.86 mm) | 0.117" (2.98 mm) | 0.125" (3.17 mm) |
| 72 | 0.162" (4.12 mm) | 0.169" (4.29 mm) | 0.180" (4.57 mm) |
| 79 | 0.178" (4.52 mm) | 0.185" (4.71 mm) | 0.198" (5.02 mm) |
| 100 | 0.225" (5.72 mm) | 0.235" (5.96 mm) | 0.250" (6.35 mm) |
| 135 | 0.304" (7.72 mm) | 0.317" (8.05 mm) | 0.338" (8.57 mm) |
| 150 | 0.338" (8.58 mm) | 0.352" (8.94 mm) | 0.375" (9.53 mm) |
| 200 | 0.450" (11.44 mm) | 0.469" (11.92 mm) | 0.500" (12.70 mm) |
| 250 | 0.563" (14.30 mm) | 0.587" (14.90 mm) | 0.625" (15.88 mm) |
| 300 | 0.676" (17.16 mm) | 0.704" (17.88 mm) | 0.750" (19.05 mm) |
| 400 | 0.901" (22.88 mm) | 0.939" (23.84 mm) | 1.000" (25.40 mm) |
| 500 | 1.126" (28.60 mm) | 1.173" (29.80 mm) | 1.250" (31.75 mm) |
| 600 | 1.351" (34.32 mm) | 1.408" (35.76 mm) | 1.500" (38.10 mm) |
| 700 | 1.576" (40.04 mm) | 1.643" (41.72 mm) | 1.750" (44.45 mm) |
| 828 | 1.865" (47.36 mm) | 1.943" (49.35 mm) | 2.070" (52.58 mm) |
Not every row is available for every paper. A standard colour paperback must have 72 to 600 pages; premium colour and black & white allow 24 to 828; a hardcover runs from 75 (76 in practice) to 550. The details are on the trim size, bleed and margins page. For hardcover, add 4.8 mm (0.189") to the figure in the table.
Calculate it directly
Spine width: —
What else the spine decides
Whether you may print text on it
KDP prints spine text only from 79 pages upwards, and the text must keep at least 0.0625" (1.6 mm) clear of each spine edge. So the usable text height is the spine width minus 3.2 mm. At 100 pages of premium colour that leaves 2.76 mm — readable, but not much. Below roughly 8 mm of spine, a title plus an author name gets tight.
On the same KDP help page, three passages say “at least 79 pages” and one says “more than 79 pages”. If your book has exactly 79 pages, add one.
The size of the whole cover sheet
The cover is a single sheet: back cover, spine, front cover, plus bleed on all four sides.
| Cover sheet | Formula |
|---|---|
| Width | bleed + trim width + spine width + trim width + bleed |
| Height | bleed + trim height + bleed |
With 0.125" (3.175 mm) of bleed, a 6 × 9 paperback of 160 premium colour pages therefore needs a cover sheet of 12.626" × 9.25" (320.7 × 235.0 mm).
You do not have to do this by hand
MenuTome is a cookbook maker for Windows. It knows your real page count, because it set the pages, and it writes the cover PDF at exactly the size worked out above — then measures the sheet of the finished file against that size and stops the export if the two do not match (a check of the sheet size, not a full print check). Its calculation was compared line by line against Amazon’s published specification on 19 September 2026: 22 of 26 individual values matched exactly.
The free basic tier needs no account and runs on your own PC. It makes one finished book of up to 15 pages, watermarked, and does not include the Amazon print package; the KDP print package — interior and cover with the calculated spine and bleed — is part of Pro. Download MenuTome for Windows · What the app actually does
Sources
Amazon KDP help pages “Create a Paperback Cover”, “Create a Hardcover Cover” and “Set Trim Size, Bleed, and Margins”, all retrieved on 19 September 2026. Amazon can change them without notice. The board thickness added for hardcover (4.8 mm) is not published by KDP; it comes from our own measurements taken against Amazon’s cover calculator on 30 August 2026 and held constant from 76 to 550 pages. Treat that one number as measured, not quoted.
Amazon and Amazon KDP are trademarks of Amazon.com, Inc. They are named here only to identify the service these specifications belong to. MenuTome is an independent product and is not affiliated with Amazon.