Return on ad spend, or ROAS, is simply how much money you made back for every dollar you spent on ads. If you spent one hundred dollars on ads and the sales those ads brought in totalled four hundred dollars, your ROAS is four. It tells the client whether the ads are actually making them money or just costing them. Most clients understand this once you frame it as money in versus money out. How do you usually break down ad performance numbers for clients who are not familiar with marketing terms?