Why your Amazon ACoS is high, and how we lower it
A brand owner writes to us with the same worry a few times a month: the Amazon ads are running, sales are coming in, and the ACoS keeps climbing. ACoS stands for advertising cost of sale, and it is one number, ad spend divided by ad sales, times a hundred. Spend $40 to make $100 in ad sales and your ACoS is 40%. A high ACoS means each dollar of ad revenue is costing you too much to earn. Here is where that money usually goes, in the order we check when we take over an account.
What a high ACoS is actually telling you
Before you touch a single campaign, figure out your break-even. Your break-even ACoS is your profit margin. If you keep 35% after the product cost, Amazon's fees, and shipping, then a 35% ACoS means those ad sales made you nothing. Anything above it means you paid to lose money on that order. Amazon says the same thing in its own advertising help: your ACoS needs to sit under your margin to turn a profit.
So the first question is never "is 40% good?" There is no universal good number, and anyone who gives you one without knowing your margin is guessing. The real question is how far your ACoS sits from your break-even, and which of the leaks below is pushing it there.
The listing is why the ads cost so much
This is the one people skip, and it is usually the biggest. ACoS is spend over sales. You can attack it from the spend side all day, but if the page converts poorly, you are pouring good ad clicks into a listing that can't close them. Every click you pay for and lose drives the number up.
We look at the main image, the title, the bullets, and the A+ content before we touch a bid. A shopper who taps your ad and lands on a dim photo and a wall of keyword soup bounces, and you paid for that bounce. Lift the conversion rate and the ACoS drops on its own, because the same spend now returns more sales. We wrote about the three listing fixes we make first if you want the specifics. Fix the page, then scale the ads onto something that sells.
You are paying for searches that never buy
When we pull the search term report on a new account, this is where we find the fast money. Amazon shows you every actual search that triggered your ad and what it did. In most accounts we take over, a real slice of the budget is going to searches that get clicks and never a sale. Someone searches for a cheaper version of your product, or a different product that sounds like yours, taps your ad out of curiosity, and leaves.
Every one of those clicks is spend with no sale on the other side, which is ACoS in its purest form. Pull the report, find the terms with real spend and zero orders, and add them as negative keywords so your ad stops showing for them. This is the least glamorous hour of the week and often the most profitable.
Your branded and non-branded traffic are tangled together
People searching your brand name already decided to buy. Those clicks convert cheap, so your branded ACoS runs low. People searching a generic category term have never heard of you, so those clicks convert worse and cost more. When both live in the same campaign, the cheap branded sales hide the expensive category ones, and the blended ACoS looks fine while the non-branded side quietly bleeds.
Split them apart. Put branded terms in their own campaign and category terms in another, and now you can see each one honestly and fund each one on its own terms. You stop overpaying for the traffic that was never going to pay you back.
Every keyword is bidding the same
A new account often has one bid doing everything. The keyword that converts at 12% and the one that converts at 2% are paying the same price per click, so half your budget is propping up targets that don't work. Cut the bids on the losers and hold or raise them on the proven winners, and the budget shifts toward the keywords that actually sell.
Amazon also lets you bid by placement: top of search, product pages, and the rest. In the accounts we run, top of search usually converts best, so paying more to sit there and less to sit on a competitor's product page tends to pull the ACoS down. These are small, boring adjustments made on a schedule, not one big lever.
What lowering ACoS actually looks like
None of this is a trick. It is a sequence: know your break-even, fix the listing so clicks convert, cut the searches that waste money, separate branded from non-branded, and bid by what each target earns. Do them in that order and the number tends to come down and stay down, instead of dropping for a week and bouncing back.
We do this work for outdoor and consumer brands every day. If your ACoS is climbing and you want a straight read on why, tell us about your Amazon account and we'll show you exactly where the money is going. No pitch, no obligation.