KDP tools
Can this book idea actually sell before you write it?
Four free calculators for Amazon KDP paperbacks, every number checked against KDP's own published specifications on 2026-09-07. No login, no email gate, nothing hidden behind a modal.
Cover calculator
Calculate your KDP paperback spine width and full wraparound cover size from page count, paper type and trim size. Inches and millimetres, with a labelled diagram.
Open the cover calculator →Royalty calculator
Work out your KDP paperback printing cost, the 50% or 60% royalty tier, your royalty per sale and the minimum list price for every Amazon marketplace.
Open the royalty calculator →Trim sizes
Every KDP paperback trim size in inches and millimetres, with minimum and maximum page counts by paper type, marketplace availability and typical uses.
Open the trim sizes →Page count estimator
Estimate how many pages your manuscript will make at a given KDP trim size, font, point size and line spacing, then carry the count into the cover calculator.
Open the page count estimator →
What comes after the calculators
The KDP keyword checker is open: competing titles, top-10 strength, buyer intent and a winnable, crowded or avoid verdict for any phrase, from a cache refreshed on a schedule. The category finder shows the Best Sellers Rank a title needs to reach #1, #10 and #20 in every Amazon Books category. The niche scanner turns one topic into the related phrases Amazon shoppers type, each scored on demand against competition, sortable and exportable as CSV. The backend-slot builder follows. The calculators tell you the book is printable and priced right. The checker tells you whether anyone is searching for it.