Tools for indie authors.
Small, free utilities from the Pendrilo studio. No login, no signup — they just work.
KDP Cover Size Calculator
Enter your trim size, page count, and paper type — get the exact spine width and full-wrap cover dimensions for Amazon KDP, in inches or millimeters, with a downloadable PDF template.
Open calculator ›KDP Royalty Calculator
What do you actually earn per sale? Compare the 70% and 35% ebook plans with delivery fees, or see paperback royalties after printing costs — plus the minimum list price KDP will accept.
Open calculator ›KDP Keyword Byte Counter
Amazon measures your 7 keyword slots in bytes, not characters — and may ignore an over-long box entirely. Count yours the way Amazon does and catch banned claims, duplicates, and wasted punctuation.
Open counter ›KDP Description Checker
Count your book description the way KDP does — 4,000 characters including HTML tags — flag unsupported markup, and clean it to Amazon's allowed tags in one click. Runs entirely in your browser.
Open checker ›Words → Pages Estimator
How many printed pages is your word count at each KDP trim size? Get an estimated page count, spine width, and reading time — then jump straight to the cover calculator, prefilled.
Open estimator ›