Most sellers either overbid (wasting money) or underbid (missing sales). Here's a systematic, data-driven approach to bid management.
The Break-Even Bid Formula
Your maximum profitable bid = Target ACoS × Average Order Value × Conversion Rate
Example: If your target ACoS is 25%, your average order value is £20, and your conversion rate is 15%, your max bid = 0.25 × 20 × 0.15 = £0.75
Bid Adjustment Rules
| Scenario | Action |
|---|---|
| ACoS below target, good impressions | Increase bid 10–15% (room to grow) |
| ACoS above target, converting | Decrease bid 10–15% (still profitable, reduce cost) |
| High clicks, no conversions (20+ clicks) | Reduce bid significantly or pause keyword |
| Low impressions, relevant keyword | Increase bid 20–30% to get data |
| No impressions at all | Check relevance, then increase bid aggressively |
Bid Adjustment Frequency
Adjust bids weekly, not daily. Amazon's algorithm needs time to respond to changes, and daily adjustments create instability. The exception: launch campaigns where you're bidding aggressively for visibility and need to react quickly to data.
Placement Adjustments
Amazon lets you increase bids for Top of Search and Product Pages placements. Top of Search typically converts 2–3x better than other placements. Start with a 50% Top of Search adjustment and measure the impact on conversion rate and ACoS.
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