The KDP Interior PDF is the file you send to the printer, so here are the exact numbers the plugin uses. Everything is measured in inches and written into the PDF as real page sizes, not scaled afterwards.
Where to find it:
Open the Publish tab, pick your book, and click Build Export Files in the Export Print-Ready Files card. Then click KDP Interior PDF to download it.
Page size by book type:
- Coloring Book: 8.5 x 11 inches, no bleed. Each PDF page is 8.5 x 11 inches.
- Activity Book: 8.5 x 11 inches, no bleed. Each PDF page is 8.5 x 11 inches.
- Journal / Planner: 6 x 9 inches, no bleed. Each PDF page is 6 x 9 inches.
- Story / Picture Book: 8.5 x 8.5 inches with 0.125 inch bleed on every side. Each PDF page is 8.75 x 8.75 inches.
What the interior contains:
- A title page with your book's title and the author name.
- A copyright page reading (c), the year and the author name, then All rights reserved, a line about reproduction, and a line saying the artwork was created with the help of AI image tools and reviewed, curated and arranged by the author.
- Your pages in page order. Picture pages that are not done yet are left out, so build after every page is finished.
The author name is your WordPress Site Title (Settings, General). Ella's site title is Ella Hart Books, so that name appears on her title pages and covers.
Resolution:
The target is 300 DPI. For each picture the plugin works out how many pixels the printed box needs, for example about 2,360 pixels across for the 7.875 inch wide picture area of a coloring page. Any picture smaller than that is upscaled to the exact size before it is placed: with fal's AI upscaler when a FLUX (fal.ai) key is saved, otherwise with a sharpened bicubic resize on your server. Pictures already big enough are used as they are.
Margins:
The outside, top and bottom margins are 0.25 inch, measured from the trim edge. On story books every margin also adds the 0.125 inch bleed, because margins are measured from the trim line, not the paper edge.
The gutter:
The inside margin on the binding side grows with the page count, so nothing is lost in the spine:
- Up to 150 pages: 0.375 inch
- 151 to 300 pages: 0.5 inch
- 301 to 500 pages: 0.625 inch
- 501 to 700 pages: 0.75 inch
- 701 pages and more: 0.875 inch
Odd pages are right hand pages, so their gutter is on the left. Even pages are left hand pages, with the gutter on the right.
How pictures are placed:
- Coloring and activity pictures are fitted inside the margins without cropping, so no line is cut off.
- Story pictures fill the whole page width and the top 70 percent of the page, running into the bleed, with the story line centered in the space below. The text starts at 14 point and gets smaller, down to 9 point, only if a long line needs it.
- Journal and puzzle pages are drawn as vector lines and shapes.
Real text, never baked in:
Titles, story lines, journal headings and puzzle instructions are real text in the PDF. They stay crisp at any size and are spelled exactly as you typed them.
A real example:
Dinosaur Friends Coloring Fun exported as a 32 page interior: the title page, the copyright page and 30 coloring pages, each 8.5 x 11 inches with a 0.375 inch gutter.
Tips:
- Always check the file in the KDP previewer before you publish. The upload checklist reminds you.
- Full color story books make big files with long build times. Export them when you can leave the tab open for a few minutes.