Break-even ACOS and ROAS calculator
Work out the highest ACOS you can afford from your real fee stack, plus break-even ROAS, maximum cost per click and the ACOS ceiling for a target margin.
Break-even ROAS of 2.35×
Enter your ad spend and ad sales above to see where you sit against the ceiling.
| Step | Working | Result |
|---|---|---|
| Profit before adsEvery currency unit of this is available to buy a sale. | $17.00 | |
| Break-even ACOSSpend above this and the campaign is buying sales at a loss. | 17 ÷ 40 × 100 | 42.5 % |
| Break-even ROAS | 2.35 × | |
| Clicks per order | 100 ÷ 10% | 10 |
| Break-even cost per clickBid above this and you lose money on the campaign at this conversion rate. | 17 ÷ 10 | $1.70 |
| ACOS ceiling to keep a 15% margin | (17 − 6) ÷ 40 × 100 | 27.5 % |
Your ad console already tells you what your ACOS is. The question it cannot answer is what ACOS you can afford, because that depends on the fee stack sitting underneath the sale. That is the gap this fills.
Questions people ask about this
What is break-even ACOS?
The advertising cost of sale at which your profit becomes exactly zero. It equals your profit before advertising divided by your selling price. If a $40 product makes $10 before ads, break-even ACOS is 25% and break-even ROAS is 4.
Is a low ACOS always better?
No. An ACOS well below break-even usually means you are underspending and leaving volume, rank and organic momentum on the table. Launch campaigns often run deliberately above break-even to buy sales velocity. The number to watch over time is TACOS — total ad spend against total revenue — because a falling TACOS with rising revenue means organic rank is taking the load.
How do I find my maximum CPC?
Divide your profit before advertising by the number of clicks it takes to make one sale. At a 10% conversion rate that is ten clicks, so $10 of profit supports a $1 bid. Bid above that and the campaign buys sales at a loss.
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Where these numbers come from
This calculator uses arithmetic rather than published rates — every figure comes from the values you enter. See the methodology page for the formulas behind it.
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