Advertising Cost of Sales (ACoS) is a metric used to measure the performance of Amazon Sponsored Product Ads. It is a percentage of unit sales spent on advertising.
ACoS calculates the correlation between the amount of money spend on advertising and the amount of money one makes as a result of that spending.
ACoS = (Ad Spend ÷ Total Sales) x 100
If you spend $15 on advertising, and it resulted in a sale of $75, then your ACoS would be (15/60)100 = 25%
Amazon Sponsored Product Ads are a type of Amazon Pay-Per-Click (PPC) advertising based on keywords and product targeting that drive traffic to a desired product detail page.