Jan 6, 2026
Advertising Cost of Sales
ACoS
Amazon's signature efficiency metric showing what percentage of ad-attributed revenue was spent on advertising. The inverse of ROAS.
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Formula:
(Ad Spend ÷ Ad Revenue) × 100
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Benchmarks
Under 25% is excellent. 25-35% is good. Amazon average ~30%. New products may run 50%+ to build ranking.
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Why It Matters
Lower ACoS isn't always better. Aggressive ACoS during launches builds organic ranking—it's an investment. Once ranked, optimize for profitability. Compare ACoS to your profit margin: if margin is 30%, ACoS above 30% loses money.
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