Guide · 5 minute read
KDP margins for puzzle books, explained
What the gutter is, why it grows with page count, and the numbers to use for a KDP puzzle book interior so the previewer shows no warnings.
Most puzzle books that bounce back from KDP review don't have bad puzzles. They have a margin that's a little too thin. The fix is simple once you know the two numbers that matter.
The two margins
The outside margin is the space at the top, bottom and outer edge of every page. For a book without bleed, KDP asks for at least 0.25 inches. If your pages print to the edge (with bleed), the minimum goes up to 0.375 inches.
The inside margin, or gutter, is the space next to the spine. This one changes with the size of your book.
Why the gutter grows
A thick book doesn't open flat. The pages curve into the spine, and anything printed too close to it disappears into the fold. So the more pages you have, the wider KDP wants the gutter:
| Page count | Inside margin |
|---|---|
| 24 to 150 | 0.375 in |
| 151 to 300 | 0.5 in |
| 301 to 500 | 0.625 in |
| 501 to 700 | 0.75 in |
| 701 to 828 | 0.875 in |
This catches people out with puzzle books in particular. You plan 140 pages, then add a solutions section, and now you're at 160. The gutter you set earlier is suddenly too thin.
Odd and even pages
On a right-hand page the gutter is on the left. On a left-hand page it's on the right. Layout tools call this "mirrored margins". If you build pages in a spreadsheet or a simple editor, it's easy to put the wide margin on the same side of every page, which leaves half your puzzles too close to the spine.
A safe setup for puzzle books
- Work out your final page count first, including the title page, the answer key and any blank page added to make the count even.
- Use the gutter from the table for that count.
- Keep 0.25 inches on the outside, top and bottom, and give puzzles a little extra breathing room on top of that so the grid lines never sit right on the limit.
- Check the whole book in KDP's previewer before you publish.
Not sure what your numbers are? The margin calculator does it for any page count, and Puzzlil sets all of this automatically, re-checking it every time the page count changes.