ROAS and Break-Even ROAS
ROAS measures revenue against ad spend, and revenue is not profit. A campaign can post an impressive-looking ROAS while losing money on every sale, because the calculation says nothing about what it cost to produce or fulfil what was sold. Break-even ROAS closes that gap by folding gross margin into the number.
Formulas
Break-even ROAS = 1 ÷ Gross margin
Gross profit = (Revenue × Margin) − Ad spend
Revenue needed = Ad spend × Target ROAS
A 40% margin business needs a 2.5 ROAS just to cover the cost of what it sold — every dollar of revenue below that ratio, relative to spend, comes out of the business rather than adding to it. The same 2.5 ROAS on a 15% margin business is a loss, since break-even there is 6.67. The margin, not the ROAS figure alone, decides whether a campaign is working.
ROAS Is Not ROI
The two get used interchangeably in casual conversation and mean structurally different things. ROAS divides revenue by spend; ROI divides profit by spend. A 4:1 ROAS could be a 300% ROI at a healthy margin or a negative ROI at a thin one — the ROAS figure alone cannot tell you which.
ROAS answers: how much revenue per ad dollar?
Useful for comparing campaigns and channels against each other quickly, and it is what most ad platforms report natively, which is why it dominates day-to-day optimisation.
ROI answers: how much profit per dollar invested?
The number that actually determines whether the business is better off for having run the campaign — it requires knowing cost of goods, which ROAS does not need and ad platforms rarely have.
Optimising for ROAS alone can hurt ROI
Pushing budget toward the highest-ROAS products can mean pushing toward the lowest-margin ones, since a cheap, thin-margin product can post a high ROAS while contributing little real profit. Check margin-adjusted numbers before reallocating spend on ROAS alone.
Setting a Target ROAS
A target ROAS should sit above break-even by a margin wide enough to cover everything ad platforms and attribution do not capture: returns, customer service cost, and the overhead of running the business at all. Setting the target exactly at break-even leaves no room for any of that.
A common approach is setting the target at 1.3 to 1.5 times the calculated break-even ROAS, giving genuine profit margin on top of covering cost of goods. Tighten it further for categories with high return rates or thin true margins once fulfilment and payment processing are included.