Free KDP Tools & Calculators
Free interactive tools and calculators for self-published authors formatting books for Amazon KDP. Calculate margins, royalties, spine width, and more.
The book studio: format your book yourself
Upload the Word file you wrote in. Get an Amazon-ready paperback PDF, a Kindle file and both covers, each checked against Amazon’s rules. Look through every page free — pay £29.99 including VAT only when you take the files.
Open the studio →EPUB vs MOBI: What to Upload to KDP in 2026
Interactive comparison of EPUB vs MOBI for Amazon KDP in 2026. Amazon deprecated MOBI for reflowable eBooks in 2021 (and for fixed-layout eBooks in 2025) — find out which format to use with our decision tree and feature comparison.
Use tool →KDP Cover Calculator — Exact Dimensions, Spine Width & Bleed
Free KDP cover calculator: enter your trim size, page count and paper type to get exact cover dimensions — full wrap width, height, spine width, bleed and safe zone — with a live diagram.
Use tool →KDP Formatting Checklist — Interactive Pre-Upload Checklist
Interactive KDP formatting checklist you can tick off as you go. Covers interior formatting, cover setup, metadata, and upload steps. Download as PDF when complete.
Use tool →KDP Margin Calculator — Get Exact Gutter Margins for Your Page Count
Calculate the exact gutter and outside margins required for your Amazon KDP paperback based on page count and trim size. Uses Amazon's official margin table.
Use tool →KDP Rejection Reasons: The 15 Most Common, Fixed (Interactive Tool)
The 15 most common KDP rejection reasons and how to fix each one — an interactive tool: pick your reason, get the step-by-step fix. Margins, cover, ISBN, fonts and more.
Use tool →KDP Royalty Calculator — Calculate Your Actual Earnings Per Sale
Calculate your exact Amazon KDP royalty per sale. Input list price, marketplace, page count, and ink type to see actual earnings for both paperback and Kindle eBook.
Use tool →KDP Trim Size Guide — Find the Perfect Size for Your Book
Interactive guide to all Amazon KDP trim sizes. Find which trim size suits your genre with UK-specific examples, bleed options, and a filterable comparison table.
Use tool →White Paper vs Cream Paper for KDP — Visual Comparison Tool
Interactive visual comparison of white and cream paper for Amazon KDP paperbacks. See how text looks on each, compare costs, and find which suits your genre.
Use tool →Word to KDP: Step-by-Step Formatting Guide
Comprehensive interactive guide to formatting a Microsoft Word document for Amazon KDP paperback upload. Covers margins, fonts, headers, page breaks, TOC, and export.
Use tool →Additional Tools
KDP Keyword Checker
Amazon lets you add up to seven keywords. Paste yours with your title and this checks them against KDP's own rules: wasted repeats, banned words, quotes and more.
Use tool →Copyright Page Generator
Build the copyright page for your self-published book, written to UK law. Asserts your moral right under the CDPA 1988. Free, runs in your browser, nothing is sent anywhere.
Use tool →KDP Spine Width Calculator
Work out your KDP paperback spine width and full wrap-around cover size from your page count, paper type and trim size — using Amazon's own published multipliers.
Use tool →KDP Royalty Calculator (UK & US)
Work out exactly what you earn per sale on Amazon KDP — paperback and Kindle, in pounds or dollars, using Amazon's own August 2026 rates including the new £12.99 / $12.99 70% band.
Use tool →ISBN Validator & Converter
Validate any ISBN-10 or ISBN-13 check digit instantly. Converts between formats and flags placeholder ISBNs.
Use tool →KDP Margin Calculator
Calculate the exact gutter and outside margins required for your KDP paperback based on page count.
Use tool →Trim Size Visualiser
Compare KDP trim sizes to scale, side by side. All 17 paperback sizes with maximum page counts by paper type, the large-trim threshold that changes your printing cost, and which size suits your genre.
Use tool →Word Count to Page Count Estimator
Estimate how many printed pages your manuscript will produce based on word count and trim size.
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