Free KDP calculators for book size, spine, margins, bleed, and metadata.
Enter the details of your paperback to calculate production dimensions and check common KDP setup choices before you format the interior or design the cover.
What can I check before formatting a KDP book?
You can confirm whether a trim size, paper type, ink choice, page count, and bleed setting work together. The calculators then show the cover size, spine width, margins, or metadata issues that follow from those choices, so you can correct the setup before rebuilding finished files.
In which order should I use the tools?
Start with the Trim Size Checker so the trim, ink and paper, and page count are a supported combination. Set the interior with the Margins and Bleed Checker, because the final page count decides the gutter and a bleed interior changes the page size. Only after the interior PDF is final, size the cover with the Cover Size Calculator and the Spine Calculator; both depend on the final even page count. Finish with the Metadata Checker before you create the listing.
Each result names the KDP rules version it was checked against, and the guides linked below explain the reasoning behind each calculation.
Do these calculators guarantee Amazon approval?
No. They provide reproducible technical checks based on the KDP rules version shown with each result. Amazon still reviews the final interior, cover, metadata, content, rights, and account. Always inspect the exported files in KDP Previewer before publishing.
Choose the calculation you need
Which guide explains the number?
Every tool answers one publishing question. These are the guides behind each calculation and the step that follows once the check passes.
Which trim size, page count, margins, and bleed setting work together for my paperback?
Check the complete combination first: a trim size, ink and paper type, and page count must be a supported KDP set, and the page count then fixes the minimum inside margin and whether the interior needs a bleed page size.
Set the format in a book projectUnderstand the decision
How wide does the full-wrap cover need to be, and how thick is the spine?
The cover width is back cover plus spine plus front cover plus bleed on both sides; the spine width is the final even page count multiplied by the paper-specific factor Amazon publishes, so the cover cannot be sized before the interior page count is final.
Prepare the cover in a book projectUnderstand the decision
How do I get from an idea and a brief to an editable manuscript I can finish?
Write the brief first, generate a structure you can edit, then draft and revise the manuscript in reviewable sections so one change never overwrites work you already approved.
Start a book project from a briefWhat should the title, subtitle, description, and keywords look like before I upload?
Check the mechanical limits first, then make sure title, subtitle, categories, and description describe the same book for the same reader; a keyword is useful when it matches how that reader searches, not because it is popular.
Draft the listing fields in a book projectUnderstand the decision
What must I check, disclose, and verify myself when AI helped produce the book?
Review facts, rights, and source material yourself, record which parts were AI-assisted or AI-generated so you can answer Amazon’s disclosure question accurately, and treat every automated check as a starting point rather than a verdict.
See what the compliance checks coverWhat does this book cost to print and produce, and what should the list price be?
Printing cost follows from the trim, ink, and page count, the list price sets the royalty after that cost, and the production budget should be estimated before generation starts, so compare these numbers before you commit to a format or a plan.
See what a book project costs in credits