About the toolkit

Why we made it

Amazon KDP sends back paperback files for small technical mistakes: a cover a few hundredths of an inch too narrow, text too close to the binding, a picture that stops short of the page edge. Each rejection means fixing the file, uploading again and waiting for another review.

The rules behind these mistakes are published by KDP, but they are spread across many help pages and tables. KDP Toolkit puts them into simple tools: enter your book size, page count and paper, and get the exact numbers and a template to design on.

How we keep the numbers right

• Every size comes from KDP’s own help pages, and each rule in our code notes where it came from.
• We tested our cover sizes against KDP’s own cover calculator for books from 24 to 828 pages, on every paper type. They match to within a thousandth of an inch.
• When KDP changes a rule, we update the tools. If you ever spot a number that doesn’t match KDP, please tell us.

Private by design

Every tool runs inside your web browser. Your book details and files are never uploaded to us. There are no accounts and no sign-up. Read the privacy policy for the details.

The tools

• Cover & spine calculator: Tell us your book size and page count. Get the exact cover size and spine width.
• Cover template generator: Download a cover template that’s already the right size, ready for Canva or Photoshop.
• 3D book mockup: See your cover on a 3D paperback at its real size, and save a picture of it.
• Margins calculator: Find out how much space to leave around your text so nothing gets cut off.
• Interior template: A free page template with the safe margins already marked for your book size.
• Bleed calculator: See how big your pages must be when pictures go right to the edge.
• Bleed vs no bleed: A simple guide: do you need bleed, and what changes if you do?
• Cover checker: Upload your cover and see what KDP would reject, before you send it.
• Interior checker: Check every page of your book for size, margins and blurry pictures.
• Cover fixer: Add missing bleed and fix the spine width automatically, and see exactly what changed.
• Check my book: Check cover and inside pages together, so the spine fits your real page count.

Not affiliated with Amazon

KDP Toolkit is an independent project. It is not made, endorsed or supported by Amazon or Kindle Direct Publishing. Amazon, Kindle and KDP are trademarks of Amazon.com, Inc. or its affiliates.

Credits

The site is built with open-source software. See credits and licenses.