What Is ACoS?
ACoS (Advertising Cost of Sales) is a key performance metric for pay-per-click advertising, especially Amazon Sponsored Products and Sponsored Brands campaigns. It tells you what percentage of your advertising-driven revenue was spent on the ads themselves. A lower ACoS means your campaigns are more efficient, while a higher ACoS signals you are spending more to generate each sale.
How to Use This Calculator
Enter your total Ad Spend (the amount you paid for clicks) and your Ad Revenue (the sales attributed to those ads) over the same period. The calculator instantly returns your ACoS percentage, plus ROAS (Return on Ad Spend) as a complementary view. Use it to compare campaigns, set bidding targets, or check whether a campaign is profitable against your break-even ACoS.
The Formula Explained
ACoS is calculated as:
$$\text{ACoS \%} = \left(\frac{\text{Ad Spend}}{\text{Ad Revenue}}\right) \times 100$$
ROAS is simply the inverse expressed as a multiplier: $$\text{ROAS} = \frac{\text{Ad Revenue}}{\text{Ad Spend}}$$ An ACoS of 25% equals a ROAS of 4x. The lower the ACoS, the higher the ROAS.
Worked Example
Suppose you spent $150 on Amazon ads and those ads generated $600 in sales. Your ACoS $$= \left(\frac{150}{600}\right) \times 100 = \mathbf{25\%}$$ That means a quarter of your ad revenue went to advertising, leaving 75% to cover product cost, fees, and profit. The corresponding ROAS is \(\frac{600}{150} = 4\text{x}\).
FAQ
What is a good ACoS? It depends on your margins. Many sellers aim for an ACoS below their profit margin (often 15–30%) so ads remain profitable. Lower than break-even ACoS means each ad sale is profitable.
How is ACoS different from ROAS? They measure the same relationship inversely. ACoS is a percentage of revenue spent on ads; ROAS is revenue earned per dollar of ad spend.
What is break-even ACoS? It equals your profit margin before advertising. At break-even ACoS, ad-driven sales neither make nor lose money before accounting for organic lift.
