Two page counts matter for a thin book. The first decides whether KDP prints it at all. The second decides whether its spine is wide enough to carry the title.
The page count limits
| Ink and paper | Fewest pages | Most pages |
|---|---|---|
| Black ink, white paper | 24 | 828 |
| Black ink, cream paper | 24 | 776 |
| Black ink, groundwood paper | 24 | 812 |
| Standard color | 72 | 600 |
| Premium color | 24 | 828 |
These are KDP's figures for its usual trim sizes, such as 5 × 8 and 6 × 9. Some of the largest sizes have lower maximums. Hardcovers run from 75 to 550 pages.
Each side of a leaf is a page, and blank pages count. KDP rounds an odd count up to the next even number. A book under the minimum gets more pages from a smaller trim size, larger type or more front and back matter.
Spine text is allowed from 79 pages
KDP's cover page says “at least 79 pages” in one place and “more than 79 pages” in another. Its Cover Creator asks for 80. At 80 pages, a book meets every reading.
The same page asks for 0.0625″ between the spine text and each edge of the spine, and for type of at least 7 points on a cover.
Allowed is not the same as fits
Spine width is the page count times a figure KDP gives for each paper. At 79 pages on white paper, that is 0.178″. Take 0.0625″ off each side and 0.053″ is left for the text, which is 3.8 points.
Seven-point type needs at least 7 points of that room. A real line needs more, because accents rise above the capitals and letters such as g and y reach below the line.
| Paper | Per page | Spine at 79 pages | Room at 79 pages | 7 pt, size alone | 7 pt line, EB Garamond |
|---|---|---|---|---|---|
| White | 0.002252″ | 0.178″ | 3.8 pt | 99 pages | 112 pages |
| Cream | 0.0025″ | 0.198″ | 5.2 pt | 89 pages | 101 pages |
| Groundwood | 0.00235″ | 0.186″ | 4.4 pt | 95 pages | 108 pages |
| Premium color | 0.002347″ | 0.185″ | 4.3 pt | 95 pages | 108 pages |
| Standard color | 0.002252″ | 0.178″ | 3.8 pt | 99 pages | 112 pages |
The last column is the one Torcul uses. A line of EB Garamond measures 1.305 times its size from its highest accent to its lowest descender. A 7-point line therefore needs 9.1 points of room.
Other typefaces measure differently. One with shorter ascenders and descenders fits a few pages sooner, and one with longer ones fits later.
What to do below that
- Leave the spine blank. KDP's own Cover Creator removes spine text that it would set smaller than 7 points.
- Put the title on the front. KDP lists a front cover without the title among its common points of failure.
- Do not shrink the type to make it fit. Under 7 points it is below KDP's minimum.
- Check the final page count. A wider inside margin, a blank page or more front matter can carry a book past the line, and the spine is set from the count you upload.
Torcul works this out from the final page count and the paper. Below the line it leaves the spine text off and says so, with the spine width, instead of setting it smaller. The spine calculator shows the spine width and whether text fits for any page count.
Sources
- Set Trim Size, Bleed, and Margins
- Create a Paperback Cover
- Cover Creator
- Paperback Submission Guidelines
None of this guarantees that KDP will accept a cover. KDP changes its help pages, so check the date on this one and on any report a tool gives you.