Free calculator

ACoS calculator

Enter Amazon ad spend and attributed ad sales to get Advertising Cost of Sales — the inverse of Return on Ad Spend, expressed as a percent.

How ACoS is calculated

ACoS = (ad spend ÷ ad-attributed sales) × 100. A 25% ACoS means you spent $0.25 in ads for every $1 of attributed ad sales — equivalent to 4× Return on Ad Spend.

Break-even ACoS roughly equals your margin %. Thin-margin ASINs need lower ACoS (or higher organic lift) to stay profitable.

ACoS % = (spend ÷ ad sales) × 100
Return on Ad Spend ≈ 100 ÷ ACoS %
Compare ACoS to margin and TACoS for full picture

Frequently asked questions

What is ACoS?

Advertising Cost of Sales is ad spend as a percentage of ad-attributed sales. It is widely used on Amazon PPC as the inverse of Return on Ad Spend.

How do you calculate ACoS?

Divide ad spend by ad sales, then multiply by 100. Example: $500 spend and $2,000 ad sales → ACoS = 25%.

What is a good ACoS?

Break-even ACoS is near your product margin. Below that, ads contribute to profit (before fees). Launch phases may tolerate higher ACoS for rank; mature ASINs usually need tighter targets.