A good ACoS leaves enough contribution to fund the business objective behind the campaign. A competitor's percentage cannot tell you what your own product can afford. Set the target from costs, required contribution and the revenue basis in your advertising report.
Build a target for each product group
Start with net revenue per unit. Subtract product cost, selling and fulfilment fees, packaging, variable storage and expected return costs. The remainder is contribution before advertising. Reserve the amount you need for overhead and profit; only the remainder is available to acquire a sale.
Target ACoS = affordable advertising cost ÷ reported revenue × 100.
Keep the denominator consistent. If your margin calculation uses net revenue and your advertising report uses a different sales basis, reconcile them before comparing percentages.
Separate the jobs your campaigns perform
Brand defence, generic acquisition and launch experiments need separate budgets and decision criteria. A low account-wide ACoS can be dominated by brand searches while generic acquisition loses money. Segment before judging performance.
For an established product, use contribution after advertising as a routine constraint. For a launch, define a maximum test loss, the hypothesis and a review date. Higher short-term spend can be intentional, but it does not guarantee organic ranking or future repeat purchases.
Turn the target into an operating decision
Review mature attribution periods and check stock availability before changing bids. If CPC rises while conversion is stable, investigate query mix and placements. If conversion falls, inspect price, delivery promise, offer availability and listing content before treating the problem as bidding alone.
Update targets when costs or prices change. Document who owns the calculation and when it was last reviewed. Track absolute contribution as well as ratios: a better percentage can still accompany a smaller business.
Use our ACoS calculation guide for reporting definitions and Business Reports analysis to diagnose the retail side. Our PPC management service connects these decisions across your portfolio.
Source: Amazon Ads on ACoS.
