Free tool
KDP Ads break-even calculator
TL;DR
Whether Amazon Ads can pay for your book is arithmetic: royalty per copy ÷ cost per click = how many clicks each sale can afford. If that implies a conversion rate cold traffic never reaches, ads lose money at any budget. Enter your numbers below for the exact break-even.
Every advertising decision reduces to one number: what a sale earns you. This calculator takes your list price, page count, and expected cost per click and tells you the conversion rate you'd need just to break even — and the ACOS to target if you do run ads.
Book keywords commonly run $0.30–$0.80 per click; competitive niches more.
Break-even is a 19% conversion rate — cold ad traffic essentially never converts that well. Improve the royalty side first: higher price, series economics, or a cheaper-to-print interior.
What if your ads convert at…
Typical book ads convert in the low-to-mid single digits. Highly specific niches — where the searcher's exact intent matches your exact title and cover — can convert several times better.
How the math works
Your royalty per copy is list price × royalty rate − printing cost (about $0.85 plus $0.012 per page for black & white). Divide that royalty by your cost per click and you get the number of clicks one sale can afford. Invert it and you get the break-even conversion rate — the fraction of ad clicks that must become purchases before you earn a cent.
Target ACOS is the same idea from Amazon's side of the dashboard: ad spend ÷ sales revenue. Your break-even ACOS is royalty ÷ list price — spend beyond that percentage and the printing cost eats your share, because printing comes out of your royalty, not Amazon's cut.
Three levers actually move these numbers: specificity (niche titles convert several times better than generic ones), series (one click that eventually sells three books doubles or triples your effective royalty per click), and the thumbnail (free, and it decides more purchases than any bid). Full reasoning in Should You Advertise Your Activity Book? Do This Math First.
Not sure about the royalty side yet? Run your book through the paperback royalty calculator first.
Thinking in series? ebookdone turns a niche idea into a finished, KDP-ready book — interior PDF, wrap cover, and metadata — from $9. Books 2 and 3 are how the ad math flips.
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