If you are reading this, your Amazon ACoS is probably higher than you want it to be. You are spending money on ads, making sales, but the margin is getting squeezed to the point where growth feels pointless.
We see this every week. And in most cases, the fix is not complicated — it is just specific. High ACoS almost always comes from one of seven root causes, and once you identify which one is affecting your account, you can fix it.
This is the exact diagnostic process we run on every new client account. Let’s get into it.
of Amazon sellers have ACoS above their target. Most do not know why — they just keep increasing budgets hoping for a better return. That never works.
First: Understand What ACoS Is Actually Telling You
ACoS (Advertising Cost of Sale) = Ad Spend ÷ Ad Revenue × 100. If you spent £500 on ads and made £2,000 in attributed sales, your ACoS is 25%.
But here is what most guides miss: your target ACoS is not the same as a good ACoS. If your product margin is 40%, an ACoS of 35% might still be profitable. If your margin is 20%, an ACoS of 25% is destroying your business.
Before you try to reduce ACoS, calculate your break-even ACoS:
Break-Even ACoS = Profit Margin %
Example: if your margin (after COGS, FBA fees, referral fees) is 32%, your break-even ACoS is 32%. Anything below that is profitable advertising.
Now you have a real target. Let’s fix your account.
Add Negative Keywords Aggressively
This is the single fastest way to cut ACoS and it is the first thing we do on every new account. Pull your search term report (last 90 days), sort by spend descending, and ask: “Would someone searching this actually buy my product?”
You will find terms like:
- Competitor brand names you do not want to target
- Colour or size variants you do not carry
- Informational queries (“how to”, “what is”)
- Completely unrelated searches triggered by broad match
Add these as exact-match negatives at the campaign level. On a typical new account audit, we find 300–500 irrelevant search terms burning budget. Eliminating them alone can drop ACoS by 4–8 percentage points within two weeks.
Fix Your Campaign Structure: Move to Single-ASIN Campaigns
If you have multiple ASINs in the same campaign, you cannot control which product gets the spend, which keywords perform best per product, or why your ACoS varies. You are flying blind.
The fix: one campaign per ASIN (or per tightly related product group). This gives you:
- Exact visibility into which product drives profit vs loss
- Ability to set different bids per product based on margin
- Clean data to make keyword decisions on
This restructure is more work upfront but it is the foundation that makes everything else work. We have seen accounts drop ACoS by 30% simply from this structural change, with no other modifications.
Reduce Bids on Underperforming Placements
Go to your campaign → Placement tab. You will see three placements: Top of Search, Rest of Search, and Product Pages. Look at the ACoS for each.
In most accounts we see Product Pages and Rest of Search running at 2–3x the ACoS of Top of Search — yet they are receiving the majority of the budget.
The fix: set bid multipliers to reduce spend on the underperforming placements. If Top of Search has 20% ACoS and Product Pages have 55% ACoS, reduce Product Page bids by 40–60% using the placement modifier. Do not pause them entirely — just reduce until they hit a profitable ACoS.
Move Your Best Keywords to Exact Match
Broad and phrase match keywords generate discovery — they help you find what customers search. But they also trigger irrelevant terms and cost more per click on average.
Once you identify your top converting search terms from the search term report, harvest them into exact match keywords in a separate campaign. Then reduce bids on the broad/phrase campaigns that found them.
This is called keyword harvesting and it is how you systematically build a high-efficiency account over time. The exact match campaigns become your profit engine; the broad campaigns keep finding new winners.
Add the harvested keywords as negatives in the broad campaign so you are not competing with yourself and driving up your own bid costs.
Improve Your Listing Conversion Rate
This one surprises people, but ACoS is directly tied to your listing conversion rate (CVR). Here is why:
ACoS = CPC ÷ (CVR × Price). If 100 people click your ad and 3 buy (3% CVR) at £25, you need your CPC to be below £0.75 to hit 10% ACoS. If your CVR improves to 5%, you can afford a CPC of £1.25 for the same ACoS.
A better listing lets you bid higher, win more placements, and still hit your ACoS target. What to fix:
- Main image — must be the best in the search results. Use PickFu to split test.
- Title — lead with the primary keyword, include key features
- Bullet points — benefits, not just features. Address objections.
- A+ Content — lifestyle imagery, comparison charts, brand story
- Reviews — below 3.8 stars kills CVR regardless of anything else
Pause or Cut Budgets on Losing Campaigns
Every account has campaigns that consistently run at 2–3x the target ACoS despite optimisation. These are not slow burners — they are structural losers.
The hard truth: pausing a bad campaign is not failure, it is discipline. Every pound you stop burning on a 70% ACoS campaign is a pound you can reinvest in a campaign running at 15%.
Our rule: if a campaign has been running for 60+ days, has had 3+ rounds of bid adjustments, and still cannot get within 20% of your target ACoS — pause it, reallocate the budget, and investigate why (wrong keywords, wrong product, wrong pricing).
Use Dayparting to Stop Spending in Low-CVR Hours
Amazon does not offer native dayparting, but you can approximate it by scheduling manual bid adjustments or using a third-party tool (Perpetua, Scale Insights, Pacvue).
Pull your hourly conversion data from Amazon Brand Analytics or your PPC tool. In most categories, CVR drops significantly between midnight and 7am. If you are spending budget in those hours at a 50% higher CPC with a 40% lower CVR, you are burning money on sleep.
Reduce bids or pause campaigns during your worst-performing hours. This alone can knock 2–4% off ACoS on accounts spending £5K+/month.
Putting It All Together: The 30-Day ACoS Reduction Plan
You do not need to do all seven at once. Here is the order we recommend:
- Week 1: Pull the search term report. Add 200+ negative keywords. This is free money — do it first.
- Week 1–2: Restructure into single-ASIN campaigns. Yes it takes time. Yes it is worth it.
- Week 2: Fix placement bids. Check the Placement tab on every campaign.
- Week 2–3: Harvest top keywords to exact match. Add negatives to source campaigns.
- Week 3–4: Audit your listing. Split test main image if CVR is below category average.
- Week 4: Pause losing campaigns. Reallocate budget.
- Ongoing: Layer in dayparting and continue weekly negative keyword sweeps.
This is the TACoS reduction we achieved for one of our clients following exactly this process — while maintaining $100K/mo in revenue. See the full case study here.
When to Get Help
These tactics work. But they take time, attention, and the ability to read data correctly. If you are also running a business, sourcing products, managing suppliers, and handling customer service — optimising PPC at this level is often the first thing that slips.
That is exactly the gap we fill. Our team manages Amazon ad accounts full time, across multiple categories and marketplaces. We have seen every broken account structure that exists and we know how to fix them fast.
Want Us to Audit Your Account?
We will review your campaigns, identify exactly where your ACoS is leaking, and show you a clear plan to fix it — free, no commitment required.
Book Free Audit Call