At some point, every indie author ends up staring at the Amazon Ads dashboard wondering whether this is a legitimate marketing strategy or an elaborate mechanism for giving money back to the company that already takes 30% of your royalties. It is, in fact, both. Whether it makes sense for you depends on a few things — and most of the advice floating around online skips the inconvenient parts.
Let's fix that.
What Amazon Ads actually are
Amazon's advertising platform — available directly through your KDP dashboard — lets you pay to have your book appear in search results and on other books' product pages. When someone searches "cosy mystery set in Cornwall" or clicks on a competitor's title, your book can show up as a sponsored result.
You pay per click, not per impression. If nobody clicks, you owe nothing. If lots of people click and nobody buys, you owe quite a lot and feel correspondingly terrible about it.
There are a few ad types available to indie authors, but the main one worth your attention is Sponsored Products — the ads that appear in search results and on product pages. Lockscreen Ads (which appear on Kindle devices when they're idle) are also available for ebooks. Sponsored Brands, the banner ads at the top of search results, require Amazon Brand Registry, which most indie authors can't access through KDP.
How the targeting works
You can run campaigns in two modes. Automatic campaigns hand the targeting over to Amazon — it decides which searches and product pages to show your book on, based on what it knows about your title. Manual campaigns let you choose your own keywords or specific ASINs (competitor books) to target.
Manual campaigns give you more control. Automatic campaigns give you data you didn't know to look for. The standard approach, and it's sound advice, is to start with an automatic campaign, let it run for a few weeks, see which keywords are actually converting, then build a manual campaign around those terms.
Keywords work on three match types: broad (Amazon shows your ad for anything vaguely related), phrase (your keyword must appear in the search query), and exact (only that precise search term triggers your ad). Exact match is more targeted and usually more efficient. Broad match burns through budget faster and occasionally serves your cosy mystery to someone searching for actual crime documentaries.
The metric you need to understand: ACOS
ACOS stands for Advertising Cost of Sale — it's your ad spend as a percentage of the revenue those ads generated. If you spent £10 in ads and it resulted in £40 in book sales, your ACOS is 25%.
What counts as a "good" ACOS varies by genre, price point, and royalty margin, but a rough working target for most fiction is somewhere under 40–50%. If you're selling a £2.99 ebook on the 70% royalty tier, your net royalty is about £2.09 per sale. Spending £1.50 per sale in ads to get there isn't terrible. Spending £4.00 isn't sustainable.
The calculation gets murkier if you're in Kindle Unlimited, because KENP page reads don't show up in Amazon's ACOS calculation — only direct purchases do. Your actual return could be better than your dashboard suggests, or it could be masking a problem. Worth keeping an eye on your page reads alongside your ad data.
When Amazon Ads work — and when they don't
Here's the bit most guides bury in paragraph eleven: Amazon Ads work significantly better for authors with multiple books in a series than for debut authors with a single title.
The maths is straightforward. If someone clicks your ad, buys your book, loves it, and then reads four more books in your series, the revenue from that reader is much higher than what Amazon's ACOS calculation credits to that initial click. Your effective cost per reader acquisition is much lower than it looks. That's the "halo effect" — one ad click, several sales.
With a single debut novel, you're hoping one click turns into one sale turns into a review that helps your organic ranking. It can work, but you're operating on thin margins. The platform tends to reward catalogue depth.
Genre matters too. Romance, thriller, crime, fantasy, and sci-fi tend to respond well because readers in those genres are actively searching Amazon by keyword. Literary fiction and niche non-fiction are spottier — the search behaviour is different, and the competition for keyword slots is less predictable.
Common ways to waste money
- Setting campaigns live and ignoring them. Amazon Ads require active management. Bids that made sense in week one may be haemorrhaging money by week four. Check in at least weekly, especially early on.
- No negative keywords. Negative keywords tell Amazon what not to show your ad for. Without them, broad and automatic campaigns will burn budget on irrelevant searches. Add negatives as soon as you see clicks with zero conversions from terms that clearly don't match your book.
- Bidding too high too soon. Start conservatively — £0.20 to £0.35 per click is a reasonable starting point for most fiction. You can always raise bids on keywords that are converting. Starting at £1.00 per click to "get impressions" is usually just expensive data collection.
- Expecting results in a fortnight. Amazon's algorithm needs time to learn which searches match your book. A new campaign typically takes three to four weeks before you're seeing reliable data. Switching everything off after ten days because nothing's happened yet is a common mistake.
The actual verdict
Amazon Ads are not a magic solution and they're not a scam. They're a tool that works when the conditions are right: when your cover converts, your book has reviews, your price is competitive, and ideally you have more than one title for a buyer to discover.
If you're launching your first book, a small experimental budget — £30 to £50 to test the water — is reasonable. Don't expect it to drive your launch. Do expect to learn something useful about which keywords your readers use to find books like yours, which is worth something even if the ACOS is ugly in month one.
If you've got a series with two or three books out and decent reviews on each, Amazon Ads become considerably more interesting and the numbers start making more sense.
The platform rewards patience, iteration, and having done the groundwork on everything else first. Getting your launch foundations right before you add paid advertising into the mix is the smarter sequence — and if you want a structured way to think through that groundwork, WIPsage is built to do exactly that.