Your ideal ACoS really depends on your margins, LTV, and how aggressive you're willing to be with customer acquisition.
Ideal ACoS = Break-even ACoS or lower.
For most, break-even sits between 15–30%, but it varies by product and channel. If your LTV is strong, you might tolerate 40–50% on the front end to scale.
Now — when ACoS creeps above target, here's the move:
1) Trim the fat.
Pause or lower bids on underperforming keywords, placements, or audiences. Cut what’s burning budget.
2) Double down on high-efficiency segments.
Identify what’s delivering conversions at or below target ACoS — then scale those with tighter bids or increased budgets.
3) Adjust match types + placements.
Move from broad to phrase or exact match (Google/Bing), or tighten audience filters (Meta, YouTube) to increase relevance.
4) Improve creative + landing pages.
Better CTRs and CVRs lower your effective ACoS. Optimize upstream before blaming the bid.
Pro tip: Use rules or scripts to auto-adjust bids when ACoS crosses a threshold. Saves time, saves margin.