A Kestrel & Vane ad spends $1,800 and is credited with 31 purchases worth $5,580, so ROAS is 5,580 / 1,800 = 3.1. With a break-even ROAS of 2.2, it makes money on each order. A second ad at 1.9 ROAS sits below the line, even though its bigger budget brought in more total revenue.

ROAS is the quickest way to compare ads on money, and it is what most teams scale or cut on. It has two blind spots: it ignores margin, so 3.0 can be great or a loss depending on your costs, and it depends on attribution, so it moves with the window and can credit sales that would have happened anyway.

Judge ROAS against your own break-even and target ROAS, not someone else's benchmark. Keep the attribution window fixed when comparing, cross-check against MER, and look for the patterns (angle, hook, product) behind your highest-ROAS ads instead of only scaling single ads.