define ROI (Return on Investment)

Definition:

Return on Investment is the amount of money you make on your ads compared to the amount of money you spend on your ads. For example, if you spend $100 on PPC ads and make $150 from those ads, then your ROI would be 50%. (Calculated as: ($150 – $100) / 100 = $50 / 100 = 50%.)

The higher your ROI, the more successful your advertising, although some practitioners in search advertising consider ROAS a more useful metric, as it breaks down cost and expenses by conversions per advertising dollar spent.