Break-even ROAS = 1 ÷ pre-ad contribution margin rate.
If an order keeps 40% of revenue after non-ad variable costs, the entire 40% is the theoretical acquisition ceiling. The corresponding break-even ROAS is 2.50×. A working target normally needs to be higher because zero profit is not a sustainable operating target.
| Pre-ad contribution margin | Contribution on $100 revenue | Break-even CPA | Break-even ROAS |
|---|---|---|---|
| 10% | $10.00 | $10.00 | 10.00× |
| 15% | $15.00 | $15.00 | 6.67× |
| 20% | $20.00 | $20.00 | 5.00× |
| 25% | $25.00 | $25.00 | 4.00× |
| 30% | $30.00 | $30.00 | 3.33× |
| 35% | $35.00 | $35.00 | 2.86× |
| 40% | $40.00 | $40.00 | 2.50× |
| 45% | $45.00 | $45.00 | 2.22× |
| 50% | $50.00 | $50.00 | 2.00× |
| 60% | $60.00 | $60.00 | 1.67× |
| 70% | $70.00 | $70.00 | 1.43× |
What the table does not include
It does not model fixed overhead, tax, cash timing, repeat purchase, attribution error or desired profit. Use the calculator for a real order-cost stack and keep a margin of safety between your working target and break-even.
Why this is shareable
Every row follows the same visible equation. There is no hidden benchmark dataset and no claim that a specific ROAS is “good” for every store.