ACoS vs TACoS
Which Amazon PPC metric should I actually optimize against?
ACoS
Option A- From
- —
- Trial
- —
- For
- —
+ Direct ROI on ad spend per campaign
− Ignores organic lift from ad-driven sessions
TACoS
Option B- From
- —
- Trial
- —
- For
- —
+ Captures whether ad spend is building durable rank
− Slower to move; harder to attribute to specific campaigns
| Dimension | ACoS | TACoS |
|---|---|---|
| Formula | Ad Spend ÷ Attributed Sales | Ad Spend ÷ Total Sales (organic + ad) |
| Time window | Daily/weekly meaningful | Monthly meaningful |
| Use for | Campaign-level decisions | Business-level decisions |
| Sensitive to organic lift? | No | Yes✓ |
| Sensitive to seasonal organic spikes? | No (clean)✓ | Yes (can mislead) |
| Healthy range | Below break-even ACoS | Falling over time |
Use ACoS for campaign decisions
ACoS is the right metric when you're deciding whether to pause a campaign, raise a bid, or shift budget between ad groups. It's clean, directly attributable, and not contaminated by organic seasonality. Break-even ACoS depends on your gross margin: a 30% gross margin product has a 30% break-even ACoS, so anything below that is profitable on a per-campaign basis.
Use TACoS for business-level decisions
TACoS is the right metric when you're deciding whether to scale your overall ad budget, evaluate a launch's health, or assess whether your ad strategy is building durable rank. A new product launch will typically show a high TACoS (say 25-40%) that gradually falls over 3-6 months as organic rank builds and ad-driven sessions become a smaller share of total sales. Falling TACoS is healthy. Rising TACoS without margin improvement is a flag.