Operator glossary
ROAS (Return on Ad Spend)
Ad-attributed revenue divided by ad spend — the inverse of ACoS (25% ACoS = 4.0 ROAS). Same number, different rhetoric: agencies quote ROAS because bigger numbers sell.
ROAS is revenue ÷ spend where ACoS is spend ÷ revenue; a 4.0 ROAS and a 25% ACoS are the same performance. Amazon's console leads with ACoS, DSP reporting leads with ROAS, and cross-channel teams coming from Google or Meta usually think in ROAS.
Whichever direction you divide, the decision line is the same: your break-even sits at 1 ÷ contribution margin. A 39.6% break-even ACoS is a 2.53 break-even ROAS. Pick one convention for the whole account and translate everything into it — mixed-metric meetings are where bad budget decisions hide.
The numbers
- ROAS = 1 ÷ ACoS. ACoS 25% = ROAS 4.0; ACoS 50% = ROAS 2.0.
- Break-even ROAS = 1 ÷ contribution margin: a 40% margin product breaks even at 2.5 ROAS.
Primary sources: Amazon Ads guides
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