ACoS (advertising cost of sales) is the share of your ad-attributed sales that went to ad spend. Divide ad spend by ad sales and multiply by 100. Enter your numbers below to get ACoS and the matching ROAS.
ACoS = ad spend ÷ ad sales × 100ROAS = ad sales ÷ ad spendAmazon reports ACoS for every campaign, ad group, keyword and search term. It only counts sales Amazon attributes to your ads within the attribution window, so organic sales are not in the denominator.
A lower ACoS means each ad dollar brings in more sales. Whether a given ACoS is good depends on your margin: compare it against your break-even ACoS (your profit per unit before ads, divided by price). Below break-even, the ads are profitable on the attributed sale; above it, you are paying for growth or rank.
Use the same date range for spend and sales, and remember Amazon's data can lag by a day or two, so very recent ACoS numbers often look worse than they end up.
You spent 25 cents in ads for every dollar of ad-attributed sales.
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There is no single good number. A good ACoS is one below your break-even ACoS for profit-focused campaigns, or a deliberate, higher number for launch and rank campaigns. Many established products aim somewhere between 15% and 35%, but your margin decides.
No. ACoS uses only sales Amazon attributes to your ads. To see ad spend relative to all sales, use TACoS (total advertising cost of sales).
They are reciprocals. ROAS = 100 ÷ ACoS, so a 25% ACoS equals a 4.0 ROAS and a 20% ACoS equals a 5.0 ROAS.
Common causes are bids above what the keyword can support, broad or auto targeting spending on irrelevant search terms, low listing conversion rate, and Amazon's reporting delay making recent days look worse. Check your search term report first.