What is a good ROAS, really? Setting targets against margin

“What is a good ROAS?” is the most common question we get, and the honest answer is: it depends on your margin, and nothing else. A 2:1 ROAS can be highly profitable for one business and a guaranteed loss for another. Here is how to find the number that is actually right for you.

Why the “4:1 rule” is wrong

You will see “aim for 4:1” repeated everywhere. It is a rule of thumb that ignores the only variable that matters - your cost of goods. If you keep 70% of every sale, a 2:1 ROAS is already comfortably profitable. If you keep 20%, even 4:1 might lose money once you add overheads. For context, ecommerce ROAS averaged roughly 2.87:1 in 2025, so “4:1” is above the norm for a whole channel.

Start with break-even

Your break-even ROAS is simply 1 divided by your profit margin. The math is quick:

• 50% margin → break-even ROAS of 2:1
• 30% margin → break-even ROAS of about 3.3:1
• 20% margin → break-even ROAS of 5:1

Below that number, every sale costs you money. Above it, you make money. That single calculation tells you more than any benchmark.

Then set a target above it

Break-even is the floor, not the goal. Your target ROAS sits above it by enough to cover overheads and leave profit - but not so high that you choke off volume. There is a real tension here: pushing the target up improves efficiency per sale but shrinks how much you can spend, because fewer auctions clear the bar. Pushing it down does the opposite.

The right target balances the two against your growth goals. A business chasing market share runs a lower target to buy volume; a business protecting margin runs a higher one. Neither is “correct” in the abstract.

Feed Smart Bidding the right number

Once you know the target, target ROAS bidding can pursue it automatically - but only if your tracking is clean. If conversion values are wrong, missing, or counting brand traffic you would have won anyway, the algorithm optimizes toward a target that does not reflect reality. That is why we rebuild tracking before trusting any ROAS target.

The short version

A good ROAS is the one that clears your break-even with room for profit and still lets you spend at the scale you want. Ignore the blanket numbers, do the margin math, and set the target from your own business. That is the difference between a benchmark and a plan.