As you know, ACoS is calculated by dividing the total spend by attributed sales. As an Amazon Marketing Agency we look at your Amazon Seller marketing data and calculate blended ACoS by dividing your ad spend by your total revenue. Your Total ACoS or TACoS takes into account the additional revenue made through organic sales, which is important to consider when analyzing the true effectiveness of your Amazon ads. ACoS is a tough metric to set as a baseline because CPCs and conversion rates vary widely, but a TACoS (ad spend / total topline) of 15% in sales growth mode is great and then ~7% as “maintenance and monetization” is also great.