ROAS & ACoS Calculator
Check whether your ads make money, and find the break-even ACoS for your margin.
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What ROAS and ACoS mean
ROAS (return on ad spend) and ACoS (advertising cost of sale) describe the same thing from opposite sides. ROAS tells you how many dollars of sales each ad dollar brought in. ACoS tells you what share of those sales you spent on ads. Amazon sellers usually talk in ACoS; most other ad platforms report ROAS.
Neither number tells you whether you made money on its own. A 4× ROAS is excellent for a product with a 50% margin and a loss for a product with a 20% margin. That is why this calculator also asks for your margin and shows your break-even ACoS: the highest ACoS you can run before ads start costing you more than they earn.
The formula
ROAS = sales from ads ÷ ad spend
ACoS = ad spend ÷ sales from ads × 100
Break-even ACoS = profit margin before ads
Profit after ads = sales from ads × margin − ad spend
Worked example
You spend $200 on ads and they bring in $800 of sales. ROAS is $800 ÷ $200 = 4.0× and ACoS is $200 ÷ $800 = 25%. With a 40% margin, those sales earn $320 before ads, so you keep $120 after paying for them. Your break-even ACoS is 40%: if ACoS climbed above that, the campaign would lose money.
How to use the break-even ACoS
- Below break-even: the campaign is profitable. Consider raising bids or budget on the keywords doing the work.
- Near break-even: fine for a product launch or for ranking, but not as a long-term setting.
- Above break-even: every sale from ads loses money. Cut weak keywords, improve the listing, or lower bids.
Frequently asked questions
What is a good ACoS?
A good ACoS is one that sits below your break-even ACoS. Many sellers aim for an ACoS 10 to 15 points under their margin so there is room for returns and other costs.
What margin should I enter?
Use the profit you make on a sale before advertising: sale price minus product cost, shipping and platform fees, as a percentage of the sale price.
Does this include sales that ads lead to indirectly?
No. It only uses the sales you enter. Ads can also lift organic sales and rankings, which is one reason some sellers accept a higher ACoS for a while.