ROI, return on investment, is net profit divided by the cost that produced it: (revenue − cost) ÷ cost, as a percentage. Unlike ROAS, it nets out every cost — media, production, fees, and goods — so it answers whether an activity actually made money.
Why it matters for agencies
ROI is the metric to judge a campaign or channel on, because it can read negative even when surface metrics look healthy. The discipline is including all the costs: a 4× ROAS can still be a losing ROI once margin and fees are counted. Use ROAS to steer day-to-day bidding and ROI to decide what to keep funding.
Run the numbers with the free ROI calculator.