The short answer: 8.5 × 11 in if you want the classic large coloring book, 8.5 × 8.5 in for a square book, 8 × 10 in for something a little more compact, and 6 × 9 in for a pocket-sized one. All four are standard KDP paperback sizes.
The rule that matters more than the choice: decide before you make the drawings. A drawing made for a tall page does not fit a square one without being squashed, cropped or left floating in white space. The size sets the shape of every page.
The four sizes, side by side
| Trim size | Shape of a drawing | Best for | Watch out for |
|---|---|---|---|
| 8.5 × 11 in | Tall, 3:4 | Kids’ books, big detailed scenes, the “classic” coloring book | More paper per page, so a higher printing cost |
| 8.5 × 8.5 in | Square, 1:1 | Adult relaxation books, gift books, mandalas and single subjects | Tall subjects (people, buildings) have to be drawn to fit a square |
| 8 × 10 in | Slightly tall, 4:5 | A generous book that is easier to hold and carry | Make sure any template or cover you use was made for 8 × 10 |
| 6 × 9 in | Tall, 2:3 | Travel and pocket books, simpler designs | Small areas are fiddly to colour; keep shapes big |
How to choose in a minute
- 1Look at the reader. Young children colour big areas with crayons and need room: go large. Adults colouring to relax often like a square book that sits nicely on a table.
- 2Look at the subject. Round things (flowers, mandalas, animal faces) suit a square. Tall things (castles, people, trees) suit a tall page.
- 3Look at the shelf. Search Amazon for your theme and note which size the books you would compete with use. Matching the norm is safe; standing out with a different size can work if it suits the subject.
- 4Look at the price. Bigger pages cost more to print, and the printing cost comes out of every sale. KDP shows it before you publish.
Bleed or no bleed?
“Bleed” means the art runs right to the edge of the page. KDP then needs the file to be slightly larger than the trim, so the edge can be cut off cleanly. Coloring pages almost never need it: line art with a white margin all round looks finished, and choosing no bleed keeps the file exactly at your trim size — one less thing to get wrong. See bleed for how it works when you do need it.
Resolution at each size
Print needs about 300 dots per inch. At that resolution a full 8.5 × 11 in page is 2,550 × 3,300 pixels and an 8.5 × 8.5 in page is 2,550 × 2,550 pixels. A drawing smaller than that will be stretched to fill the page, and its lines will print soft or jagged. Check the size of every image before it goes into the book, especially AI-generated ones, which are often made smaller than print needs.
Choose a size and BookArc draws every page in that shape, at 300 dpi, ready for KDP.
See the coloring book makerFor the whole process — niche, drawings, interior, cover and upload — read how to make a coloring book to sell on Amazon KDP. For spine and cover measurements, the trim size entry and the spine width calculator have the details.
