Break-Even ROAS The floor a campaign has to clear
Break-even ROAS is the point where a campaign stops losing money and has not yet started making any. It comes straight out of your gross margin, and out of nothing else:
break-even ROAS = 1 ÷ gross margin
At a 40% margin that is 2.5x. Below it you are paying for the privilege of shipping orders.
| Gross margin | Break-even ROAS |
|---|---|
| 20% | 5.00x |
| 30% | 3.33x |
| 40% | 2.50x |
| 50% | 2.00x |
| 60% | 1.67x |
Read it upwards and the squeeze on thin margins is obvious. A 20% margin needs five dollars back for every one spent before anything is left over, which rules out most competitive keywords before you have bid on anything.
It is a floor, not a target
This is where it goes wrong in practice. Somebody works out the break-even figure, sets it as the campaign target, and the account then runs for months at exactly zero contribution after product costs. Rent, salaries, software, returns — none of that is in the number.
Break-even covers variable costs. Nothing else. A target ROAS has to sit above it, and how far above depends on your own fixed-cost base rather than on any benchmark. Most ecommerce teams plan about a third higher. That is a habit, not a law.
The number moves when your margin moves
Because the formula only takes one input, anything that touches margin resets the floor on the same day. A 20%-off promotion on a 40% margin product drops the margin to roughly 25%, and the break-even ROAS jumps from 2.5x to 4.0x. Same campaign, same bids, and it is now unprofitable without a single setting having changed.
Rising cost of goods does the same thing more slowly, a fraction of a point at a time, and that one is harder to catch because no single week looks any different from the week before it. Worth recalculating whenever the product side moves.
From the floor to a bid ceiling
Break-even ROAS alone will not tell you what to bid. Two more steps get you there.
Your maximum cost per acquisition is the contribution one order leaves behind: average order value times gross margin. At $100 and 45%, that is $45.
Your maximum cost per click scales that by how often a click converts. At a 2% conversion rate, $45 × 0.02 gives $0.90. Bid above it and you lose money over enough clicks, however good a short window looks.
The break-even ROAS calculator runs both steps and shows where the ceiling lands for your own numbers.