Comparison
TACoS vs ACoS: which metric should you actually optimise?
TACoS is the business metric. ACoS is the tactical one. Knowing when to use each separates the operators who hit P&L targets from the ones who hit campaign dashboards.
| TACoS | ACoS | |
|---|---|---|
| What it measures | Total ad spend / total revenue | Ad spend / ad-attributed revenue |
| Best for | Business and P&L decisions | Campaign-level efficiency comparisons |
| Captures cannibalisation? | Yes | No |
| Reports up to CFO? | Yes - lives next to CM2 | No - internal-only number |
| Sensitive to organic shifts | Yes (catches stockouts, hijacking) | No - blind to organic |
| Right cadence | Weekly account / daily SKU bucket | Campaign-level on tactical decisions |
Use TACoS when
When you need to know if the account is healthy and tied to the P&L. When the conversation is with finance.
Use ACoS when
When you are comparing the efficiency of two campaigns inside the same SKU bucket. When testing bid changes, placement modifiers, or creative refreshes.
Operator's verdict
Use TACoS as the business metric you report on, target against, and ladder spend to. Use ACoS for tactics inside campaigns. If you only watch one number, watch TACoS.