High ACoS is the single most common complaint we hear from Amazon sellers. The instinct is always the same: lower bids until the number comes down. But cutting bids blindly usually cuts sales faster than it cuts cost — and your ACoS barely moves.
Lowering ACoS the right way means improving efficiency, not just spending less. Here's the framework.
Start with conversion, not bids
ACoS is downstream of conversion rate. If your listing converts poorly, no amount of bid tuning will save your ACoS — you're paying for clicks that don't become sales. Fix the listing first: main image, title, price competitiveness, and reviews. A 1% lift in conversion often does more for ACoS than a week of bid cuts.
Separate your search terms from your campaigns
Run a search-term report and split spend into three buckets:
- Winners — converting terms. Protect and scale these.
- Wasters — high spend, no sales. Negative-target them.
- Watchlist — early terms with potential. Give them a controlled budget.
Most accounts have 20–40% of spend sitting in the "wasters" bucket. Cutting that is free ACoS improvement with zero sales loss.
Restructure, don't just rebid
Tight campaign structure — separating exact, phrase, and broad match, and isolating your best converters into their own campaigns — gives you control. You can fund what works and starve what doesn't, instead of averaging good and bad together.
Think in TACoS, not just ACoS
ACoS only measures ad sales. TACoS (total advertising cost of sales) measures ad spend against total revenue, including organic. A campaign with a scary ACoS that's driving rank and organic sales may be your most profitable lever. Judge the whole picture.
The takeaway: lower ACoS by being more efficient, not just cheaper. Want us to audit where your ad spend is leaking? Book a free audit.