FREE · 5 QUESTIONS · 60 SECONDS

Find out why your Amazon ads are losing money

Answer 5 questions and see exactly which part of your KDP ad strategy is leaking budget — and what to fix first.

QUESTION 1 OF 5

What is your average ACoS?

Why most KDP authors lose money on Amazon Ads — and what the data actually shows

Running Amazon Ads for your KDP books is one of the fastest ways to grow sales. It is also one of the fastest ways to burn through money with nothing to show for it. Most authors who struggle with Amazon Ads are not making dramatic mistakes. They are making small, consistent ones that compound quietly over months.

This page exists to help you diagnose exactly which category your campaigns fall into — and give you a clear starting point for fixing it.

The real reason your ACoS is too high

ACoS stands for Advertising Cost of Sales. It is the percentage of a sale that you spent on ads to get it. If your ACoS is 80%, you spent $0.80 in ads for every $1.00 in sales revenue. Most KDP authors need an ACoS below 40-50% to be profitable, depending on their royalty rate.

High ACoS is almost never caused by bad luck. It is caused by one of three things:

Many KDP authors waste 30% or more of their Amazon Ads budget on searches that were never going to convert. The money is not lost to bad luck — it is lost to the absence of a weekly optimisation system.

The search term report: the most valuable document most authors never open

Your search term report shows every search term that triggered one of your ads, how many clicks it received, how much it spent, and how many sales it generated. This is the single most important document in your KDP advertising. Yet the majority of KDP authors either do not know it exists or check it once every few months.

A weekly search term report review typically takes 15 to 20 minutes and will usually surface three to five terms that have been spending with zero sales, one or two terms worth promoting to exact match, and a handful of negatives to add. That is the entire system.

How to calculate your break-even ACoS

Divide your royalty per sale by your list price, then multiply by 100. If your book is priced at $9.99 and you earn a $3.50 royalty, your break-even ACoS is 35%. Any keyword with an ACoS consistently above 35% is costing you money on every sale it drives.

Frequently asked questions about Amazon KDP advertising

What is a good ACoS for KDP books? +
A good ACoS depends on your royalty rate and your goal. For most KDP authors on the 70% royalty tier, a break-even ACoS sits between 30% and 50%. Under 40% is considered healthy for a book generating consistent sales. During a launch phase it is normal to run at a higher ACoS to build sales velocity and ranking.
Why are my Amazon Ads getting clicks but no sales? +
Clicks without sales almost always point to one of three issues. Your listing is not converting, you are showing ads for searches that are not buyer-intent searches, or your book is positioned incorrectly for the search terms you are targeting. The Listing Audit inside KDP Rank Fuel is designed to diagnose exactly which of these is happening.
What are negative keywords and why do they matter? +
Negative keywords tell Amazon not to show your ad when a search contains that term. Without them, your campaigns will spend money on searches that have nothing to do with your book. A good negative keyword list is built incrementally over time from weekly search term report reviews.
How long does it take for Amazon Ads to start working? +
Most new KDP campaigns need two to four weeks to generate enough data to optimise meaningfully. Many authors give up before this point, concluding that ads do not work for their book, when in reality the campaign simply has not had enough time to find its profitable terms.
Should I run Amazon Ads on a book that is not selling organically? +
In most cases, no. Amazon Ads can accelerate sales for a book that already converts, but they cannot fix a book with a weak listing or positioning problem. The more useful first step is to audit your listing, identify what is stopping readers from buying, fix it, and then use ads to amplify the results.
How often should I review my Amazon Ads? +
Weekly is the right cadence for most authors. Monthly gives Amazon enough time to generate meaningful data between cycles, but weekly catches budget-capping winners and obvious waste faster. Avoid daily — Amazon's attribution window means very recent data is often incomplete.