Return on Ad Spend (ROAS) is a marketing metric that measures the revenue generated for every dollar spent on advertising. It helps businesses evaluate the effectiveness of their advertising campaigns by showing how much money they earn compared to their ad investment. A higher ROAS indicates a more successful campaign. To calculate ROAS, divide the total revenue from ads by the total ad spend. For example, if a company spends $1,000 on ads and earns $5,000 in revenue, the ROAS would be 5. This means the company earns $5 for every $1 spent on advertising, highlighting the campaign's profitability.