The best trim size and paper for a puzzle book

The sizes puzzle publishers actually use

KDP offers sixteen paperback trim sizes, from 5 x 8 in up to A4. Puzzle books mostly use four of them, and those are the four Gridbinder makes: 6 x 9 in, 8 x 10 in, 8.5 x 11 in (US Letter) and A4 (8.27 x 11.69 in).

KDP calls a trim "large" when it is wider than 6.12 in or taller than 9 in. Large trims pay a higher printing cost per page on Amazon.com: $0.017 per page instead of $0.012 for black ink books over 110 pages.

Grid size is the real question

A 9 x 9 Sudoku needs cells big enough to write a digit in, and pencil marks if your readers use them. A 15 x 15 Nonogram needs room for the clue numbers above and to the left of the grid as well. On a 6 x 9 in page with half-inch margins there are only 5 inches of width for all of that.

The comparison below shows the same puzzle type at two sizes. On 6 x 9 in with two per page, each Sudoku grid is about 3 inches wide; on 8.5 x 11 in with one per page, the grid fills most of the width of the page.

Page count and printing cost

On Amazon.com, a black ink paperback of 24 to 110 pages costs a fixed $2.30 to print on a regular trim and $2.84 on a large trim. Above 110 pages the cost is $1.00 plus $0.012 per page (regular) or $0.017 per page (large).

So a 200-page 6 x 9 in book costs $1.00 + 200 x $0.012 = $3.40 to print, while the same 200 pages at 8.5 x 11 in cost $1.00 + 200 x $0.017 = $4.40. A larger page also holds more, so the same 100 puzzles may need fewer pages at 8.5 x 11 in. Compare the whole book, not the page.

Use the free calculator to see the printing cost, spine and cover size for any trim and page count.

White or cream paper

For black ink, KDP offers white and cream paper at the same printing cost. Cream is a little thicker (0.0025 in per page against 0.002252 in), so the spine is wider. Many novels use cream because it is easy on the eyes for long reading. Puzzle books are written in, and white paper gives the most contrast for thin grid lines and small clue numbers. Colour printing is only on white paper.

Readers sometimes ask whether markers show through KDP paper. KDP's black ink papers are 50 to 61 lb (74 to 90 GSM). Pencil and ballpoint are the safe tools to mention in your book description.

A simple way to choose

1. Decide who the reader is: commuter, senior, puzzle fan who wants hard grids, teacher who photocopies.
2. Pick the largest grid your hardest level needs, and the trim where that grid fits with good margins.
3. Make a sample at that size and print one page at 100% on a home printer. Write in it.
4. Check printing cost and list price with the calculator before you commit to a series.