Break-even ROAS is the return on ad spend at which advertising revenue exactly covers its costs, calculated as one divided by your gross margin. Any ROAS above it is profit; below it, you are paying to lose money.
Why the target ROAS is not break-even
Break-even ROAS is 1 ÷ gross margin. On a 25% margin product you need a 4:1 ROAS just to break even, so a 4:1 that looks healthy is actually zero profit. This is why a raw ROAS number means nothing until you know the margin behind it.
Setting targets from it
Once you know break-even, you set a target ROAS above it that leaves the profit you need. It is the honest anchor for a Target ROAS bid strategy: aim below break-even and you are instructing the platform to buy unprofitable revenue.