Free KDP coloring-book interior checker
Turn any coloring pages into a KDP-accepted interior PDF
Did Amazon KDP (Kindle Direct Publishing) reject your interior, or do pages print faint? The usual causes are wrong trim, missing margins, under-300-DPI, and bleed set up wrong. Drop your book in for a free per-page check that tells you exactly which — then fix it in one click: every page fit to your KDP trim with safe margins, lines forced to bold pure-black, all combined into one upload-ready PDF at 300 DPI — no-bleed or full-bleed. 100% in your browser — nothing is uploaded.
Independent tool — not affiliated with or endorsed by Amazon / Kindle Direct Publishing (KDP).
↑ A real, untouched sample run through this tool — no upload needed. Drop your own pages below.
Sign in to start rendering
Create a free account with Google to turn your coloring pages into a KDP-ready interior PDF — rendered right here in your browser. Your images never leave your device.
Continue with GoogleNo credit card. We use your Google account only to sign you in.
Web rendering
Free- One upload-ready interior PDF — every page fit to your KDP trim with safe margins (gutter auto-sized to page count), at 300 DPI, no-bleed or full-bleed.
- Watermark-free & unlimited — as many books and pages as you like, exported as true grayscale (DeviceGray).
- Crisp bold-black lines, scanner speckle cleaned — 100% in your browser, images never leave your device.
↑ Drop your pages above and render — free with your account.
High-resolution AI
Coming soon · Paid- AI line-art cleanup — rebuild broken or fuzzy scans into crisp, pure line art.
- Upscale to 600+ DPI — enlarge small or low-res art without softening, GPU-accelerated.
- Batch-enhance a whole book — one click, every page, then straight into your interior PDF.
Pricing to be announced. Everything on the left stays free while we build this.
How it works
Three steps, about a minute
Drop your pages
Select every interior page (PNG or JPG). They’re read locally in your browser — nothing is uploaded to any server.
See the free check
Every page is scored for resolution and faint lines, with an on-screen before/after preview of the print-ready fix.
Export one PDF
Get a single 300-DPI interior PDF — no-bleed or full-bleed, every page fit to your trim with KDP-safe margins and bold black lines.
FAQ
What KDP self-publishers ask
Why did KDP reject my interior?
The three most common reasons for a coloring-book interior are wrong trim size, no margins / content too close to the edge, and images below 300 DPI. Prepressly fixes all three: it refits every page to the exact KDP trim you pick, insets content to a KDP-safe margin, and rasterizes at a true 300 DPI.
Is the KDP interior checker free?
Yes — free while in early access. The per-page check, the on-screen before/after, and the full watermark-free interior PDF export are all free once you sign in with your Google account. No credit card, no subscription. (A future High-resolution AI tier will be paid — see below.)
Will my files be uploaded anywhere?
No. Everything runs in your browser using JavaScript — your images are read and processed on your own device and never sent to a server. You can even disconnect from the internet after the page loads and it still works.
No-bleed or full-bleed?
Both — you choose on export. No-bleed (default) sizes each page to the exact trim with KDP-safe white margins — right for standard line-art coloring pages. Full-bleed enlarges the page to KDP’s exact bleed spec (trim + 0.125″ wide, + 0.25″ tall) and fills the art edge-to-edge — for mandala, pattern and zentangle books designed to print to the edge. Either way there’s no bleed math for you to get wrong.
Does it embed fonts or make a cover?
No — and it doesn’t need to. Pages are exported as images, so there are no fonts to embed (a common source of KDP errors). You still design and upload your cover separately.
Do I need an account? What will be paid later?
You sign in once with Google — that unlocks the full renderer and unlimited watermark-free exports, free while in early access. The only paid tier planned is High-resolution AI (AI line-art cleanup + upscaling to 600+ DPI), which is coming soon; join the waitlist and today’s features stay free.
What page sizes are supported?
The most common KDP coloring-book trims: 8.5×11, 8×10, 8.5×8.5, 8.25×8.25, 7×10, and 6×9 inches. Every page is fit to the trim you choose.
Free while in early access. Sign in with Google and render as many books as you like, watermark-free. Something not right with an export? Email support@prepressly.com and a human will help.
Free KDP guides
Publishing a coloring book on KDP? Start here
Why KDP rejected your interior
Wrong trim, margins, gutter, DPI, bleed, faint lines — the exact numbers to fix each error.
AI pages print gray on KDP
Why Midjourney / Stable Diffusion line art prints muddy — and how to force it to pure black.
Trim & margin cheat-sheet
Pick a trim + page count → exact PDF size, safe margins and binding gutter.